问题

Many people can’t learn any lessons from the mistakes they’ve made __________ they get hurt somehow.

A:whether
B:unless
C:if
D:as

正确答案是：

同类题型

Have you ever ________ the Great wall

Measles ______ a kind of infectiousillness

It was _____ by the railway board that thecost of rail fares would be increased by ten percent

Look at the math book. Do you know ______ it might be

If you visit Italy, you can go to____and take photos there.