涡轮工作在极端条件下是指：（）.
A.靠近喷管
B.总温总压高
C.极高的温度和转速
D.需要输出功率
参考答案：C
简述近距离放疗技术。
It was obvious that the ship ______ on its voyage without _______ from the officials in charge or it
would not have sailed off so secretly. [ ]
A. set off; a permission
B. set out; permission
C. set off; permit
D. set out; a permit
