There are many mistakes in your homework. You should ______ special attention to the correct use of tenses.

The total population of China _______ about 1300 million on January 6, 2005. And about eighty percent _______ still farmers. [ ]

______ your sister late for school again

The guide said that much attention must ______ these details.

It will make ______big difference if this experimentbecomes ______ success.