My deskmate is still a puzzle to me; at one moment he is quiet while at another he _____ be quite active.
| A．can | B．must | C．should | D．would |
This means going back to the place where we left the family ____ in a tree the night before.
| A．to sleep | B．to be sleeping | C．slept | D．sleeping |
The children talked so loudly at dinner table that I had to struggle ____.
| A．to be heard | B．to have heard | C．hearing | D．being heard |
Peter earns ____ his brother does.
| A．as much twice as | B．twice as much as |
| C．much as twice as | D．as twice much as |
____ in the fields on a March afternoon, he could feel the warmth of spring.
| A．Walking | B．To walk | C．Walked | D．Having walked |
Only when I left my parents for America ____ how much I loved them.
| A．I realized | B．I had realized | C．had I realized | D．did I realize |