The police are looking into the cause which ________ the sinking of the ship with about 200 passengers aboard.
She couldn' t find her son_ she had dropped him off.
33.I told them not everybody could pass the test,____?
—When shall we start the reconstruction of the old buildings? —Not until_ by the local government.
The man has been in____ doctors describe as a vegetative (植物的) state for six years.
But for the fact that I_ an unexpected visitor, I _____to the lecture.