Conjunctions and prepositions

Although/ though/ even though/ In spite of/ despite

A. After 'although' we use a subject + verb
A1. Compare: We went out although it was raining. Vs. We didn't go out because it was raining.

B. After 'in spite of' or 'despite', we use a noun, a pronoun (this/ that/ what etc.) or ~ing. (e.g. In spite of the rain, we enjoyed our holiday.)
B1. can say 'in spite of the fact (that) ~ and despite the fact (that) ~ (e.g. I didn't get the job in spite of the fact (that) (= despite the fact (that)) I had the necessary qualifications.
B2. We went out in spite of the rain. vs. We didn't go out because of the rain.

C. I couldn't sleep although I was very tired. (= despite being very tired. (not despite I was tired))

D. Sometime we use though instead of although
D1. In spoken English we often use though at the end of a sentence. (e.g. The house isn't very nice. I like the garden though. (= but I like the garden)
D2. Even though (but not 'even' alone) is a stronger form of although. (e.g. Even though I was really tired, I couldn't sleep. (not Even I was really tired~)

In Case

A. I'll remind them about the meeting in case they've forgotten (= because it is possible they have forgotten)
A1. We use just in case for a smaller possibility.
A2. Do not use will after in case. Use a present tense for the future. (e.g. I'll leave my phone switched on in case Dul calls. (not in case Dul will call)

B. In case is not the same as if. We use in case to say why somebody does something. You do something now in case something happens later.
B1. We'll buy some more food in case Jay comes. Vs. We will buy some more food if Jay comes.

C. can use in case + past to say why somebody dis something. (e.g. I left my phone switched on in case Dul called. (= because it was possible that Dul would call))
C1. In case of is not the same as in case. In case of ~ = if there is ~ (especially on notices etc.)

 

Unless, As long as, Provided/ providing

A. Unless = even if (e.g. I'll see you tomorrow unless I have to work late. (except if I have to work late)
A1. Instead of unless it is often possible to say if ~ not (e.g. Unless we leave now, we'll be late.)

B. As long as or so long as, and provided (that) or providing (that): All these expressions mean 'if' or 'on condition that'.
B1. Providing or provided (that) the room is clean, I don't mind which hotel we stay at.

C. When you are talking about the future, do not use will after unless/ as long as/ so long as/ provided/ providing. Use a present tense.
C1. I'm not going out unless it stops raining. (not unless it will stop)

 

As (As I walked along the street…/ As I was hungry…)

A. As = at the same time as
A1. you can use 'as' when two things happen at the same time. (e.g. We all waved goodbye to Ann as she drove away.
A2. You can say that something happened as you were doing something else (in the middle of doing something else)
A3. also use just as (= exactly at that moment) (e.g. Just as I sat down, the phone rang.)
A4. also use as when two things happen together in a longer period of time. (e.g. As the day went on, the weather got worse.)
A5. as: two things happen at the same time (e.g. As we walked home, we talked about we would have for dinner. (=at the same time))
A6. When (not as): one thing happens after another. (e.g. When we got home, we started cooking the dinner. (not as we got home)

B. As = Because
B1. As I was hungry, I decided to find somewhere to eat. (= because I was hungry)
B2. Since: Since we have plenty of time, let's go and have a coffee.
B3. As they lived near us, we used to see them quite often. (=because they lived near us)
B4. When they lived near us, we used to see them quite often. (= at the time they lived near us)

Like and as

A. Like = 'similar to' or 'the same as' (e.g. What a beautiful house! It's like a palace. (not as a palace)
A1. In above sentence, like is a preposition. So it is followed by a noun (like a place), a pronoun (like me/ like this) or ~ing (like walking).
A2. also say '~ like" (somebody/ something) doing something' (e.g. What's that noise? It sounds like a baby crying.)

B. Sometimes like = for example. (e.g. Some sports, like motor-racing, can be dangerous.)
B1. also use such as (=for example). (e.g. Some sports, such as motor-racing, can be dangerous.)

C. As = in the same way as, or in the same condition as. We use as before subject + verb (e.g. You should have done it as I showed you.)
C1. Like is possible in informal spoken English. (e.g. I left everything like it was.)
C2. You should have done it as I showed you. (or like I showed you) vs. You should have done it like this. (not as this)
C3. You're late as usual. As always, Jon was the first to complain.

D. Sometimes as (+ subject + verb) has other meaning.
D1. You can do as you like. (= do what you like), They did as they promised. (= They did what they promised)
D2. also say as you know (= you know this already)/ as I said/ as she expected/ as I thought (= expected this before) etc.
D3. Like is not usual in these expressions, except with say (like I said)

E. As can also be a preposition, but the meaning is different from like. (as = same, like = similar)
E1. As (preposition) = in the position of, in the form of etc. (e.g. A few years ago I worked as a taxi driver. (not like a taxi driver))

As if/ as though/ like

A. can use as if or as though to say how somebody or something looks/ sounds/ feels. (e.g. That house looks as if it's going to fall down. And That house looks like it's going to fall down)
A1. You look tired (look + adjective) vs. You look as if you haven't slept. (look as if + subjective + verb)

B. can say It looks as if ~ / It sounds as if ~ (e.g. Do you hear that music next door? It sounds as if they are having a party.)
B1. use as though or like. (e.g. It looks as though she isn't coming. Or It looks like she isn't coming.)

C. can use as if or as though with other verbs to say how somebody does something. (e.g. He ran as if he was running for his life.)
C1. In informal spoken English, you can also use like .

D. After as if (or as though), we sometimes use the past when we are talking about the present. (e.g. I don't like Tom. He talks as if he knew everything.)
D1. She's always asking me to do things for her - as if I didn't have enough to do already. (I do have enough to do)
D2. When you use the past in this way, you can use were instead of was. (e.g. Why do you talk about him as if he were (or was) an old man?

By and until, By the time

A. By (= a time) = not later than. (e.g. This milk has to be used by 25 April.
A1. use until (or till) to say how long a situation continues.
A2. Something continues until a time in the future. (e.g. Jon will be away until Monday. (so he'll be back on Monday))
A3. Something happens by a time in the future. (e.g. Jon will be back by Monday. (= he'll be back not later than Monday))

B. can say 'by the time something happens'. It's too late to go to the bank now. By the time we get there, it will be closed. (=the bank will close between now and the time we get there)
B1. can say 'by the time something happened' (for the past). (e.g. Jon's car broke down on the way to the party last night. By the time he arrived, most of the other guests had left. (it took him a long time to get to the party and most of the guests left during this time), I had a lot of work to do yesterday evening. I was very tired by the time I finished. (= it took me a long time to do the work, and I became more and more tired during this time))
B2. Also by then or by that time. (e.g. Jon finally arrived at the party at midnight, but by then (or by that time), most of the guests has left.)