79.　　 We will make as many improvements as possible in our work.

78.　　 Xiao Hong’s composition is quite satisfactory. I’m sure her teacher will be satisfied with it.

77.　　 Generally speaking, acid rain is the result of the development of industry.

76.　　 Many books and magazines can provide us with mental food.

75.　　 To save money, you may go there by bus instead of calling a taxi.

74.　　 Such a question as that is easy to answer.

73.　　 Li Mei is ill and her teacher decides to help her make up for the lessons she missed.

72.　　 It is necessary and important for the students to learn a foreign language well.

71.　　 On hearing the sad news, she couldn’t help crying.

70.　　 But for his timely help, I couldn’t have overcome so many difficulties.