I. can also use that (instead of who), but you can't use which for people. (e.g. Do you know anyone who/ that speaks French and Italian?)
a. cannot use that for people when we give extra information (e.g. John, who (not that) speaks French and Italian, works as a tourist guide.)
b. When we are talking about things, we use that or which (not who) in a Relative clause. (e.g. I don't like stories that have unhappy endings. (or stories which have~))
c. That is more usual than which, but sometimes you must use which. (e.g. Bob told me about his new job, which (not that) he's enjoying very much.)
d. can leave out who/ which/ that when it is the objective. (e.g. We stayed at the hotel (that/ which) you recommended.)
e. cannot leave out who or which when we give extra information. (e.g. We stayed at the Park Hotel, which a friend of ours recommended.)
Idiom 365
I jumped out of my skin: gave a big jump
Example: I jumped out of my skin when I heard the bang.