A government official was murdered in his own house yesterday and the police   are collecting evidence that is ______ to the case.          

Keep the camera ________ when you take a picture.

On the celebration of the university’s 100th birthday, he said, “I have never experienced __________ time here as a graduate of Tsinghua University.”

The new group of students is better-behaved than the other group who stayed here __________. 

—Mary, let’s go to the bookshop this weekend. Will you be ______?  —Sorry, but I’m going to visit my uncle in the countryside.