Most of the sandstorm in our country in spring from March to May.
A. happen B. happens C.is happening
—_____will you stay here? —Until tomorrow afternoon．
| A．How long | B．How soon |
| C．When | D．How often |
My shoes are worn out．They need_______．
| A．to repair | B．be repaired |
| C．repaired | D．repairing |
_______ Andy was playing，his mother came home．
| A．While | B．Until | C．Although | D．Since |
一Look! There is a small bridge on the river．
一It ________ two days ago．
| A．built | B．was built |
| C．has built | D．has been built |
It is said that the gravity on Mars is only about __________ of the gravity on earth．
| A．three-eighths | B．third-eighth |
| C．three-eighth | D．third-eighths |