fail
［误］ Tom failed his exam.
［正］ Tom failed in his exam.
［正］ Tom failed to pass the exam.
［析］ fail为不及物动词，其后可用in加名词，或直接接不定式。
family
［误］ I'm sorry I have to go. Tom's families are waiting for me.
［误］ I'm sorry I have to go. Tom's family is waiting for me.
［正］ I'm sorry I have to go. Tom's family are waiting for me.
［析］ family是集合名词，把它当作整体看它是单数，如看作家庭中的每个成员则为复数。如：Your family are very kind to me. My family is very large.
