I have been living in the United States for twenty years,but seldomso lonely as now.
| A． | have I felt | B． | I had felt | C． | I have felt | D． | had I felt |
Water, _____ we cannot live, exists in the form of liquid, gas or solid.
| A．from which | B．on which | C．without which | D．by which |
It still remains a question _____ life exists on any other planet in the solar system.
| A．why | B．whether | C．how | D．where |
The old lady likes to keep things in the house, _____ throw them away, though many are useless.
| A．more than | B．but also | C．as if | D．rather than |
Most of the evidence was destroyed in the fire. _____, it would be almost impossible to prove Jim guilty.
| A．Anyhow | B．However | C．Besides | D．Thus |
_____ John won a gold medal in the English competition really excited his family.
| A．That | B．when | C．which | D．what |