改错题,每题有一个错误,例:can改成can't。 1 Henry mustn’t be at home because he phoned me from the farm just now. 2. Jack is a bilingual person. He may speak English and Japanese. 3. Mary can know the answer to the question. I’m not sure. 4. You mayn’t tell anyone about this — it’s a secret. 5. Mother is out, so I must look after the shop.