定语从句中先行词作表语必须用that吗?答:everything, anything, nothing, none, the one等代词时,如:Is there anything that I can do for you? That’s all that I know.2. 先行词前有only, any, few, little, no, all, one of 等修饰语时,如: You can take any seat that is free. There is little time that we can ...