—____ the workers are very tired, ____they keep on working.
— They are great. We must learn from them.
| A．Because; / | B．Though; / |
| C．Because; so | D．Though; but |
—Why are you so happy, today?
—Because I to London with my parents tomorrow.
| A．fly | B．flew | C．am flying | D．have flown |
The computer in 1946 in America.
| A．is invented | B．was invented | C．invents | D．invented |
—You praise your son. He works harder than before.
—Thanks, I will.
| A．should | B．can | C．may | D．must |
Our team tried our best, we failed the match at last.
| A．but | B．and | C．or | D．while |
the morning of March 31, she made an important decision in her life.
| A．Since | B．In | C．From | D．On |