单项选择题

There are still many problems _________ before we are ready for a long stay on the Moon.

A．solving
B．solved
C．being solved
D．to be solved
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单项选择题
_________ I have a word with you It won’t take long.
A．Can
B．Must
C．Shall
D．Should
单项选择题
Last night, there were millions of people _________ the opening ceremony live on TV.
A．watch
B．to watch
C．watched
D．watching
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