It was not until mid-night _____ he went back home after the experiment.
| A．when | B．/ | C．that | D．before |
E-mail, as well as telephones, ______ an important part in daily communication.
| A．is playing | B．have played | C．are playing | D．play |
To improve the quality of our products, we asked for advice had used the products.
| A．which | B．who | C．whichever | D．whoever |
His first book next month is based on a true story.
| A．published | B．to be published | C．to publish | D．being published |
The next morning she found the man ___________ in bed, dead.
| A．lying | B．lie | C．lay | D．laying |
No matter what you have achieved, you have no reasons to _____others in your field.
| A．look on | B．look up to | C．look forward to | D．look down upon |