拼写单词根据句子意思，在空格中填写适当的单词，使句子完整、正确。（共8分）

小题1:February is the                month of the year.

小题2:The box is very light, so I can lift it by            .

小题3:I can’t help you          you tell me what’s wrong.

小题4:As a citizen, we mustn’t do anything         the law.

小题5:Lucy was very         , so she drank two glasses of water.

小题6:Susan's parents were disappointed when they knew Susan            the exam.

小题7:If I           my father's birthday, please remind me.

小题8:The book          to Alice because her name is on it.

带有______的类称为抽象类，它只能作为______来使用。