It’s time that I ____ on night duty. I must be off now.-I’d rather you ____ at home on such a family reunion night. [ ]

More public kindergartens　　　preschool kids can spend their fun-filled childhood will be built this year.

It was not until the 18th century that manrealized that the whole of the brain was involved in the working of the mind，

you go with us to theNational Park— Well, it _______.

31．Every solid object______reflect a sound，varying according to the size and nature of the object．