In the past several weeks, many cities in Northern China from heavy fogs and severe cold.
| A．had suffered | B．have been suffering | C．were suffered | D．suffered |
The students in the university are all taking courses _______ a degree.
| A．coming to | B．going to | C．leading to | D．turning to |
. _______ different kinds of pianos, the workers farther improved their quality.
| A．To produce | B．Being produced | C．Produced | D．Having produced |
A person _______ a foreign language must be able to use the foreign language _______ all about his own.
| A．to learn, to forget | B．learning, to forget | C．to learn, forgetting | D．learning, forgetting |
.The wallet _______ several days ago was found _______ in the dustbin outside the building.
| A．stolen, hidden | B．stealing, hiding | C．stealing, hidden | D．stolen, hiding |
.Lessons _______ easily were soon forgotten.
| A．to learn | B．learn | C．learned | D．learning |