建筑石膏凝结很快,终凝时间在______min以内;硬化后抗压强度较高,长期强度增长______。
参考答案:30;很快
----I’m sorry, but making a telephone call is not allowed in the meeting-room.
----Oh, I_____that, Sorry, I don’t do that again.
A.don’t know
B.didn’t know
C.won’t know
D.haven’t known