Amy isn’t as quiet as she ______. She is quite outgoing.

___ is believed ___ more and more people would fly to the moon in the future.

I’d like to help the homeless people in the earthquake. －You ________ join a volunteer group.

Be careful when you take exams. Check your paper to ________ there are no mistakes before you hand it in.

Liu Xiang has failed over and over again in the past years. And that’s _________ he succeeds.