温升试验时，当顶层油温升的变化率小于每小时（）并维持3小时，油面温升达到稳定。
A.0.5K
B.1K
C.1.5K
D.2K
参考答案：B
He managed to make himself ______ with his _______ English. [ ]
A. understood; breaking
B. understand; broken
C. understood; breaking
D. understood; broken
我国实行的是______制度，提倡18--55周岁的健康公民自愿献血．
