I have no idea whether he has sisters, and if he does, _____？[ ]

Studies show that people are more tosuffer from back problems if they always sit before computer screens for longhours.

.The public ______ generous in theircontributions to the earthquake victims.

He doesn’t speak English as _____ as Chinese.—Maybe, perhaps it’s just because Chinese is his native language..

Well done!— Thanks. But ______ a few more minutes, I could have done it still better. [ ]