In the past few years, My Heart Will Go On was a popular song among young people, ____ were often heard singing it at parties．
| A．they | B． that | C． who | D．which |
.______ the beginning of the 19th century did scientists know that all matter is made up of 
atoms.
| A．At | B．By | C．Up to | D．Not until |
Many people believe that _______ will takes years to develop a car that does not pollute the air.
| A．it | B．that | C．there | D．this |
They have been woking on this project for one month. It seems they need ________ month to finish it.
| A．more | B．other | C．another | D．the other |
________your generous help, we could not be living a happy life today.
| A．Despite | B．But for | C．Because of | D．As long as |
.After they were given several terrible blows, the enemy did not _____ out after dark.
| A．dared to come | B．dared come | C．dare to come | D．dare coming |