He smiled politely ______ Mary apologized for her drunken friends

－What do youthink of the party last night－Wonderful!It’s years I enjoyed myself somuch.

the team finished most of their research work?—Yes, but the rest rather difficult

Many students listened to the lecture, but I wondered how much work they took________[ ]

China’s population is expected to increase to about 1.5 billion, ____ it will start to decline slowly.