Air pollution, together with littering, ____ many problems in our large industrial cities today.
| A．causes | B．cause | C．caused | D．causing |
He suddenly saw Sue _____ the room. He pushed his way ____ the crowd of people to get to her.
| A．across, across | B．over, through | C．over, into | D．across, through |
No one helped me . I did it all ______myself .
| A．for | B．by | C．from | D．to |
To understand the grammar of the sentence，you must break it______ into parts．
| A．down | B．up | C．off | D．out |
The classroom is big enough ______, but we’ll have to move if we have more students.
| A．for the moment | B．on the moment | C．in a moment | D．for a moment |
—You know. Bob is a little slow ____ understanding, so…
— So I have to be patient ______ him.
| A．in ; with | B．on; with | C．in; to | D．at; for |