66. A number of students ________ in flats, and others live in the nearby holiday resorts, where there is a reasonable supply of competitively priced accommodation.

　　A) revive C) gather

　　B) inhabit D) reside

　　67. He bought his house on the________ plan, paying a certain amount of money each month.

　　A) division C) installment

　　B) premium D) fluctuation

　　68. He could not ________ ignorance as his excuse; he should have known what was happening in

　　his department.

　　A) petition C) resort

　　B) plead D) reproach

　　69. Many ecologists believe that lots of major species in the world are on the________ of extinction.

　　A) margin C) verge

　　B) border D) fringe

　　70. Any salesperson who sells more than the weekly ________ will receive a bonus.

　　A) ratio C) allocation

　　B) quota D) portion