1.(2018·北京卷)____________ we don’t stop climate change, many animals and plants in the world will be gone.
答案:If
2.It occurs to me that it is a long time ____________ I have lived in Thailand.
答案:since
3.It was quite a long time ____________ I figured out what had happened to the manager.
答案:before
4.(2019·福州高二月考)Actually, ____________ we’ve done a lot to develop a lowcarbon economy, it doesn’t live up to our expectations.
答案:though/although/while
5.____________ you change your mind,I won’t be able to help you.
答案:Unless
6.He tried his best to solve the problem, ____________ difficult it was.
答案:however