.He said he _________ experiments those days.
| A．was doing | B．had been doing | C．has been doing | D．is doing |
The trip will take about five months；it will be a long time ________ we meet them again.
| A．after | B．before | C．since | D．when |
This kind of medicine has a bad ________on our brains.
| A．affection | B．affect | C．effect | D．result |
The chance I had been looking forward ________ at last.
| A．to came | B．to come | C．to comes | D．to coming |
The musicians were to play jokes on each other as well as play music，most of ________ was based loosely on the Beatles.
| A．that | B．them | C．which | D．whom |
Studies show that _____ good health depends on _____ balanced diet and plenty of rest and exercise.
| A．不填; a | B．the; a | C．the; 不填 | D．不填; 不填 |