safe；wet；true；nine；give away；put away；dry

76．The writer wrote his　　book when he was fifty．

77．It has rained much this year，so the south of China is　　than usual．

78．Children should be taught road　　to avoid road accidents．

79．Even though we are busy studying，we are supposed to　　our things in our bedrooms．

80．We can't understand our teachers　　took care of us until we graduate．