1.whether可置于句首引导主语从句,而if不能。
2.whether可用在介词之后,引导宾语从句,而If则不能。 如: Success depends on whether we make evough effort. 3.whether可引导表语从句,if则不能。 如: The puestion is whether it is not worthdoing. 4.在名词之后引导同位语从句时,用whether而不用if。 如: The puestion whether the students answered correctly should be decided by the teacher. 5.whether后可接不定式,而if不能。如: Please tell us whether to go or stay here. 6.在有些动词(如discuss)之后,只能用whether,而不用if引导宾语从句。如: We discussed whether we should close the shop. 7.在引导否定概念in宾语从句时,只能用if,而不用whether.如:he asked me if I hadn't finished my work. 8.whether 可以和 or not 连用,if不能。 |
|