单项选择题

The librarian requires that all books ______ returned before the last day of classes.

A．are
B．be
C．must be
D．would be
<上一题 目录 下一题>
热门 试题

填空题
What’s one of the advantages of the tour according to the advertisementYou may have a 5-tour-route choice for only ________.
单项选择题
Why does land become desert after all trees are cut down
A．Because nothing remains on land except floods.
B．Because there are no longer trees to keep the rain and protect the top-soil.
C．Because too much rain sinks in and washes away the top-soil.
D．Because roots of the trees break up the soil.
相关试题