用所给动词的适当形式填空。 1. They are trying______(save) the boy by doing everything. 2.—Why not______ (have)a rest? —Good idea. 3. You'd better______ (not play) football in the street. 4. When they______ (find) the lost child, the mother was very grateful. 5. He used to______ (take) a walk after supper. 6. They are used to______ (quarrel) with each other. 7. When the police arrived, the wounded (send) to the hospital. 8. If you are too lazy, you______ (not pass) the exam. 9. Jim said he ______ (come) from the USA. 10. Look! There is a cat ______ (climb) up the tree.