【C8】A．requireB．demonstrateC．performD．fulfil

【B7】A．makeB．printC．performD．produce

【C16】A．to requireB．requiredC．requiringD．are required

【C5】A．requireB．requestC．urgeD．appeal

【C17】A．RequireB．RequiringC．To RequireD．Required

【C17】A．digestB．exploreC．performD．calculate

Unfortunately he could not ______ the danger at that time.A、prepareB、pretendC、performD、p