When you do Reading Part 5, you should look at the words before and after the gap. Look at gap (1). The word before the gap is a verb, ‘belonging’. This word is always followed by the word ‘to’ and then a noun so we know that ‘to’ has to be the missing word. In gap (2) the word before is ‘to’ so we need a verb in the gap. The verb has to go with the word after the gap which is ‘friends’. We can use the verb ‘make’ to fill this gap. In gap (3) the verb before the gap is ‘looking’.
Looking can be followed by ‘for’ or ‘at’ and here it means to try to find something so ‘for’ is the correct answer.