13. Recently I bought a house, _______ was very reasonable.
| A．which price | B．whose the price | C．of which price | D．the price of which |
Scientists have to work hard to keep ________ with modern discoveries and developments.
| A．company | B．track | C．pace | D．touch |
The child was told to ________ for being rude to his uncle.
| A．excuse | B．apologize | C．pardon | D．thank |
The two girls had been talking in ________ low voice all ________ time during the meeting, which upset the manager.
| A．a; / | B．/; / | C．/; the | D．a; the |
Only after they had discussed the matter for a few hours ______ a decision.
| A．they reached | B．did they reach | C．they reach | D．do they reach |
— Why was it so noisy over there?
— The Twins were surrounded by their fans ____ they stepped out of the hall.
| A．until | B．the moment | C．in case | D．so that |