86. You can make your dictionary use much more efficient if you only look up the words which are necessary to understand the text
87. Even if you can't work out the meaning exactly, you may be able to get a vague idea, enough to enable you to continue reading.
88. He said that setting aside time for improving his physical fitness would be a total misuse of his working hours.
89. By watching and learning from a model, you will probably begin to identify and adopt good working habits.
90. He collected much money from his friends and posted it to the people in the earthquake area.
81. Had it not been for his help, we couldn't have overcome all the difficulties.
82. It is time that we finished our work.
83.Unfortunately they hadn't taken the heavy traffic into account and it was too late to catch their flight when they got to the airport
84. Once you have worked out a study plan, you should put it into practice.
85. He hopes to catch up on the lessons he missed during the weekend.