Listen! Helen is singing in the next room.—It ____be her. She has gone to Beijing.

The government of the United States began at once toinvestigate the case ______ a lot of students were killed.

I was on the highway _______ this car went past followed by a police carThey ______ at least 150 kilometers an hour[ ]

The ____ is just around the corner and you won’t missit.

We were surprised to hear that the reason_______ she gave for her absence was______ her mother was ill.—Yes，we saw her mother was at the supermarket that morning.