The method recommended by WHO is in accuracy, but it is too demanding in operation and it consumes too many laboratory animals.
We should do what we can to save those _____ species, including the tiger, an animal which was considered _____ to humans.
—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure. A. can; mustB. can; may . must; can D. may; must
I am not fond of ______ music very much, but I do like ______ music they are dancing to.
A survey has found that many medical workers would not choose the profession __________ a second chance, citing high stress and tense patient-doctor relationships.
— Was it 11 o'clock your father came back last night? —Yes, he is always coming back so late.