He gave us another piece of advice, ________ of great help to the research work.
| A．which I think is | B．which I think it is |
| C．I think which is | D．I think it is |
Students can easily fall behind in their studies ____ they don’t manage their spare time carefully.
| A．though | B．if | C．since | D．until |
He warmly congratulated them on _____ they had achieved in science and technology.
| A．that | B．where | C．what | D．which |
_____ of concrete and steel, the Petronas Towers in Kuala Lampu could provide a better chance of surviving than did the World Trade Centre buildings.
| A．Building | B．Built | C．To built | D．Having built |
Would you consider lying to a good friend to avoid ____ your friend’s feelings？If so, what kinds of things would you lie about?
| A．hurting | B．to hurt | C．being hurt | D．hurt |
It is not until recently ______ the scientists have found proof of there being water on Mars.
| A．when | B．that | C．how | D．what |