______ in his studies, he didn’t know that all the others had left.
Mum, have you seen my mobile phone?—The one you bought last week? I’m sorry I haven’t seen ________.
It’s important __________ us students to make a plan __________ our studies before a new term starts.[ ]
_____ will you go back from Hong Kong?—In 3 days.[ ]
More and more parks ________in Mentougou in five years.