—Does Liu Hui serve in the army? —No, but he ________ in the army for three years.
Many students _____ to learn a traditional Chinese art form, such as Peking opera.
If we don’t take some measures to protect this kind of plant, it will ____ soon.
–Do you know who invented _______ telephone? - No, but it is really _______ most useful invention.
——Excuse me! Sir, is the swimming pool open all day? ——________.Only from 6:00 p.m. to 10:00 p.m.
——Are you satisfied with his answer? ——Not at all. It couldn’t have been________.