nothing ??

　　［误］ Nothing but books were sold here.??

　　［正］ Nothing but books was sold here.??

　　［析］ 要注意真正的主语是nothing而不是books，所以这一结构在学生的使用中经常出错。

　　［误］ I have nothing to do but to cry.??

　　［正］ I have nothing to do but cry.??

　　［析］ 在这一结构中but后面要用省to的不定式。??

　　number ??

　　［误］ A number of news can be heard on TV today.??

　　［正］ A lot of news can be heard on TV today.??

　　［析］ a number of后接可数名词复数。??

　　［误］ The number of students are ten thousand.??

　　［正］ The number of students is ten thousand.??

　　［析］ a number of 其意为"大量的"，而the number of…是"某某的数量"。即the number of students意为"学生人数"，所以要用单数形式的谓语动词。??