must 肯定、may 可能 大、might 小、may not 可能不 might not can't 不可能、couldn't + do(be) 现在或将来 have done 过去 (二)三级试题汇编 1、The house is dark; the Browns ___ to bed. A. may go B. should go C. should have gone D. must have gone 2、—Tha...