Those who have trouble _____ can grow crops vertically on trellises.
| A．bending | B．bent | C．bend | D．to bend |
The boy seems __________ a lot of books, for he knows so much.
| A．that he has read |
| B．to read |
| C．has read |
| D．to have read |
He is so addicted to smoking that __________ seems to be no chance of talking him into quitting.
| A．this |
| B．what |
| C．it |
| D．there |
The Roman Empire __________ for several centuries.
| A．exists |
| B．existed |
| C．was existed |
| D．is existing |
-How long has the United Nations __________？
-__________1945.
| A．come into existence; In |
| B．been in existence; Since |
| C．been in existence; From |
| D．come into existence; For |
It seems __________ the poor guy is going to die of __________.
| A．that; scare |
| B．as though; fright |
| C．as if; frighten |
| D．that; scared |