用单词的正确形式填空。（每题1分，共10分）

小题1:It was quite terrible. It took me some time to c______ myself  down.

小题2:I'm terribly sorry. I didn't do it on p__________.

小题3: Though I haven’t met him for many years, I could r__________ him immediately when I saw him in the crowd.

小题4:I am d__________ to change my job. No one else can change  my mind.

小题5:Whether you will succeed or not in doing the work depends on your  a________ to it.

小题6:Water can be turned into ________(蒸汽) when heated.

小题7:Because of the global warming, there are more and more natural _______.（灾难）

小题8:He thought I had known the fact. But _______,(事实上 ) I knew nothing about it.

小题9:He is a stubborn person. No one can _______him.(说服，劝说)

小题10:The workers made great efforts to ________（营救，援救） the people who were trapped underground.

保持氢气化学性质的粒子是（　　）

A．H

B．H⁺

C．H₂

D．2H