Samuel Clemens，______ Mark Twain, wrote many popular stories.
| A．was known as | B．known as |
| C．was known for | D．known for |
It remains________ whether Jim will be fit enough to play in the finals.
| A．seen | B．to be seen | C．seeing | D．to see |
Professor Williams keeps telling his students that the future________ to the well-educated.
| A．is belonging | B．is belonged | C．belongs | D．will be belonged |
There is no doubt _______ my friend is not satisfied with what they have done.
| A．that | B．whether | C．if | D．why |
We should learn from those _____ are always ready to help others.
| A．who | B．whom | C．they | D．that |
Friends should be_____ about each other’s feelings.
| A．crazy | B．hidden | C．concerned | D．worried |