While Helen ________ the piano，her mother came in．
| A．was playing | B．is playing | C．played | D．plays |
The shorts are _________ of all, but they are _________．
| A．best, cheaper | B．better, dear |
| C．the best，dear | D．good, cheap |
The room was dark，_________ I turned on the lights．
| A．and | B．or | C．but | D．so |
----________ have you been studying at school?
----For more than four years．
| A．How often | B．How long | C．How old | D．How far |
My history teacher said that I ________ do better．
| A．can | B．could | C．was | D．was can |