1.Because he was ill yesterday, so he didn't go to work. (×)

　　Because he was ill yesterday, he didn't go to work. (√)

　　He was ill yesterday, so he didn't go to work. (√)

　　[析] 用though, but表示"虽然……，但是…… "或用because, so 表示"因为……，所以……"时，though和but 及because和so 都只能择一而用，不能两者同时使用。

　　2.The Smiths have moved Beijing. (×)

　　The Smiths have moved to Beijing. (√)

　　[析] 不及物动词后接名词或代词作宾语时，要在动词之后加上适当的介词;但不及物动词后接home, here, there等副词作宾语时，动词之后不必加任何介词。

　　3.The box is too heavy for him to carry it. (×)

　　The box is too heavy for him to carry. (√)

　　[析] the box既是这句话的主语, 也是不定式to carry的逻辑宾语，若句末再加上it，就和the box重复了。

　　4.Each of the boys have a pen. (×)

　　Each of the boys has a pen. (√)

　　[析] 复数名词前有表个体的each of, one of, every，either of等词组修饰，或有表否定的neither of, none of 等词组修饰时，谓语动词要用单数形式。

　　5.例:那是你心软!我不就是一个例子吗?

　　Neither he nor you is good at English. (×)

　　Neither he nor you are good at English. (√)

　　[析] either... or..., neither... nor..., not only..., but also... 等词组连接句子的两个主语时，谓语动词遵循"就近一致原则", 即由靠近谓语的那个主语决定谓语的人称和数用何种形式。

　　6.Ten minus three are seven. (×)

　　Ten minus three is seven. (√)

　　[析] 用英语表示加(plus)、减(minus)等数学运算时，谓语动词也用单数形式。

　　7.The number of the workers in this factory are about 5,000. (×)

　　The number of the workers in this factory is about 5,000. (√)

　　[析] the number of表示"……的数量"，谓语动词用单数形式;a number of 的意思是"若干"或"许多"，相当于some或a lot of，和复数名词连用，谓语动词用复数形式。