____________ you are sure there are no gas leaks, don't light any matches.
A: If
B: When
C: As
D: Unless
A: If
B: When
C: As
D: Unless
举一反三
- Don’t use abbreviations unless you’re quite sure your writer will understand them.
- –Don’t forget to turn off the light when you leave. --- I _________. A: mustn’t B: won’t C: don’t D: can’t
- —Are you sure ______ you've met him before A: unless B: that C: when D: though
- You won't succeed ____ harder. A: unless you work B: unless you don't work C: if you will work D: if you won't work
- Never force a connector into a port. If the connector and port don’t join with reasonable ease, they probably don’t match. Make sure that the connector matches the port and that you have positioned the connector correctly in relation to the port.