烧结速率的影响因素：（）、（）、（）。
参考答案：颗粒半径；粘度；表面张力
The old scientist took up walking as a regular form of exercise, which, of course, is of great to his heath.
A．benefit
B．favor
C．sense
D．relationship
结核性胸膜炎出现（）
A.肺源性呼吸困难
B.心源性呼吸困难
C.血源性呼吸困难
D.中毒性呼吸困难
E.神经、精神性呼吸困难
