The idea for the new plan came to his mind, to his experiment in the lab.
| A．while devoting | B．while devoting himself |
| C．while he was devoted | D．while devoted |
The boss ______ the worker how to do it, or the accident couldn’t have happened.
| A．can’t have told | B．ought to tell | C．could have told | D．mustn’t have told |
In the 1930s, the two countries were at ______ war, and his father was fighting at _____ front.
| A．the; 不填 | B．不填; the | C．the; the | D．不填;不填 |
Don't leave for there until__________ to do so.
| A．you'll be told | B．told | C．telling | D．you are told |
Tom’s teacher kept on telling him to practise speaking English, but _______ didn’t work.
| A．he | B．which | C．all | D．it |
These plants are watered___________
| A．each other day | B．every other day | C．each of two days | D．every of two days |