_______ is well known _______ Hong Kong returned to China on July 1st, 1997.
They thought my suggestion reasonable _______a few experts to help them.
_____but he still couldn’t understand the logical connection of the two subjects.
It was not until he came back _____ he knew the police were looking for him.
All her time _______ experiments, she has no time for films.
Some students are now busy preparing for the “Independent Recruitment(自主招生)” contest, in hopes of getting a “Pass” card at their first _______.