I found the trick is to break it down into the stages set  and within that paragraph you are looking for 

the words have/had  or has (or the negative version of those word haven't hasn't) which is then followed by a verb in the past tense

example

“Michael,” I cried out. “I haven’t seen you for ages. Come on, sit down

you can see the word haven't the verb following it is in the past tense "seen" so the answer is seen

another example

“No, no.” Michael started to tuck into his pie, chips and beans. “I’ve been too busy studying.

slightly tricky this one as the I have has been changed to I've its then followed by a verb in the past tense been so the answer is been

hope this helps im not a teacher I just used this methodology to crack that exercise