The answer is how many,as an adverb typically describes how things are done in a certain manner,the place,time,etc;
1a) We've Been here FOR an hour.
1b) We've been here SINCE 4 o' clock.
2a)She hasn't spoken to me FOR 2 weeks.
2b) She hasn't spoken to me SINCE last week.
3a) They've live in this street SINCE 1970.
3b) They've lived in this street FOR a long time.
4a)I haven't had time to do it SINCE last Monday.
4b) I haven;t had time to do it FOR a few days.
5a) We haven't bought a new on SINCE ages.
5b) We haven't bought a new one FOR many years.
Answer:
Cool! I've been studying A LOT lately. What about you?
Answer: Write about something that happened in your life that had a big impact on you/helped to make you who you are.
Explanation: For example, if you were an only child and suddenly you have a younger sibling, you could write about how that changed life in your household. So think about some things that have happened in your life and identify something that affected you (negatively or positively).