They arrived at a farmhouse, in front of ______sat a small boy.
| A．whom | B．who | C．which | D．that |
Black clouds had completely ___ the sun.
| A．blocked off | B．broken out | C．blocked out | D．broken off |
It was an unpleasant subject ____ we _____ for a long time.
| A．about which…discussed | B．about which…argued |
| C．over them…argued | D．which…argued |
It must have rained last night, ________ the ground is wet now.
| A．for | B．because | C．since | D．now that |
The serious expression of the captain kept his crew _________.
| A．in the distance | B．from a distance | C．in a distance | D．at a distance |
The tomato juice left some _____ on a customer’s skirt, which made the waitress nervous.
| A．signs | B．points | C．tracks | D．spots |