.______ the beginning of the 19th century did scientists know that all matter is made up of 
atoms.
| A．At | B．By | C．Up to | D．Not until |
No matter what you say, I shall________my opinion.
| A．carry out |
| B．keep up |
| C．go on |
| D．stick to |
The Panama Canal________the Atlantic________the Pacific.
| A．connects; with |
| B．joins; with |
| C．unites; with |
| D．joins; up |
—He promised to come to see you.
—But he________. I've been alone.
| A．doesn't |
| B．didn't |
| C．won't |
| D．hasn't |
—Come on, Shela. I want to show you something.
—Oh, how nice of you. I________you ________to bring me a gift.
| A．didn't think; were going |
| B．never think; are going |
| C．never thought; were going |
| D．hadn't thought; were going |
—What were you doing when Tom came to see you?
—I________on my overcoat and________to visit a friend of mine.
| A．have just put; leaving |
| B．was put; was left |
| C．had just put; was leaving |
| D．was putting; left |