The teacher told us to remain silent unless _____.
| A．to be asked | B．being asked | C．asked | D．you asked |
_______, ice can be changed into water and water can be changed into steam.
| A．Heat | B．Heating |
| C．To heat | D．Heated |
--- How do you want to post it?
--- It is only printed matter;_______ mail is OK.
| A．general | B．ordinary |
| C．necessary | D．partial |
---Do you know what a computer system ________ ?
---Hardware and software. Am I right?
| A．consists of | B．consists in |
| C．is consisted of | D．is consisted in |
Michael’s new house is like a huge palace, _______ with his old one.
| A．comparing | B．compares |
| C．to compare | D．compared |
_____ of the city ____ destroyed in the war that broke out in 1945.
| A．Two-thirds, were | B．Two-thirds, was |
| C．Two-third, was | D．Two-third, were |