What a big snake! It ________ one meter and a half in length.

After the examination，my teacher told me that failure _______the mother of success.

Yesterday if the policeman _______earlier, the fight between the two boys would have been prevented. 

—How long have you been doing that? —Since I       her for the first time. 

When he looked up, he suddenly found himself       by a group of teenagers,       looked at him anxiously.