People go out with masks,________.
In order to make students have a good knowledge of science subjects, they are encouraged to______ their own science experiments.
No one knew where my grandfather was, and many came to _____us in searching for him.
—Is the People’ Great Hall _______to ordinary visitors?—Of course.
What a sunny weather today! Let's hope it_______ for Saturday's tennis match.
Because of the heavy foggy weather, we had to _______ the plan of going to Xi’an for the football game by air.