单词拼写（共10小题；每小题1分，满分10分）

小题1:Because the temperature dropped a________（突然） , the south of China suffered a heavy snow.

小题2:Please come to my home to play cards whenever it is______________ (方便) for you.

小题3:Books should be c___________ by subjects.

小题4:Don’t h_____________ to turn to me whenever you are in trouble.

小题5:The doctor said that the patient might be _________________(不舒服) after the operation.

小题6:The ancients were ________________(错误) in their belief that the earth was flat.

小题7:R_____________ of the colour of his skin, every man has right to live where he wants to.

小题8:It is not polite to i_________ when someone is talking.

小题9:I can’t ____________(假设) anything in this case.

小题10:The explorers had to eat unripe fruits to prevent____________(饥饿).

金属切削加工的主要形式有哪些？