Measures must be ______ to keep the factories _____ going on polluting the rivers[ ]

Here comes the train. Let’s_____.

The Dragon Boat Festival is coming. I’m going to give a talk about it to the exchange students.—Great! But don’t forget to tell them _________.

When is Jay’s concert — It’s ______ three o’clock ______ the afternoon of July 18th.

Thousands ofchildren saidthey were forced to practice the piano.