Our teacher told us that we must be strict ______ ourselves ______ our study. [ ]

_ _ will he visit his friend?—in a month?[ ]

Whose shirt is this? Is it Tom’s? — No, it isn’t. _______ is white.

What’re you going to do to protect the environment? — Plant trees on side of the river.

One of the most interesting places in Yangzhou ________ are often visited by foreigners is the West Slender Lake. [ ]