69. Keep in mind that it is a shame to waste (浪费) food. 解题技巧:浪费在动词不定式后面填原型即可。 70. It was brave (勇敢的)of Mary to quit her job and start her own business. 解题技巧:在系动词之后填形容词。 71. I'm happy that 80-year-old grandma ...