A. Conjunction: is a word used to connect words, phrases, clauses, sentences or to coordinate words in the same (e.g. and, but, if, while, or although. etc.).
A1. The Conjunction type: coordinating conjunction, subordinating conjunction, and correlative conjunction.

B. In spite of, despite and although are all used to show a contrast but there are differences in the structures used with them.
B1. After ‘although’ we use a subject + verb 

C. We use in case to talk about things we should do in order to be prepared for possible future situations. 

D. Unless = except if (e.g. The club is for members only. You can’t go in unless you are a member (=except if you are a member))
D1. As long as or So long as / Provided (that) or Providing (that) = if or on condition that 

E. As/ Because/ Since: As = at the same time as. The structure of the sentence is usually: as + subject + verb 
E1. Because is more common than as and since, both in writing and speaking. When we use because, we are focusing on the reason. 
E2. We often use as and since when we want to focus more on the result than the reason. 

F. As/ Like: Like = ‘similar to’ or ‘the same as’ 

G. As if/ Though: We also use as if to make comparisons. The verb after as if is always in the past subjunctive. If the verb be directly follows as if, we use were for all personal pronouns.

H. For/ During/ While: use for + a period of time to say how long something goes on.

I. By and until, By the time: By (+a time) =not later than. 

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