Mary has got a full mark in the test. She ______ very hard all these days.    A. will work                                B. may work    C. must have worked                        D. could have worked
Mary has got a full mark in the test. She ______ very hard - Unit 4 Practical Writing - 魔“方”作文——大学英文写作 - U校园 | 大学网课搜题引擎