目前国内外奶粉生产中采用加热喷雾干燥的方式有（）喷雾干燥和离心式喷雾干燥。
参考答案：压力式
木材物理力学性质的转折点是（）。
A.含水率
B.湿胀干缩
C.纤维饱和点
D.各向异性
It has been announced that candidates remain in their seats until all the papers have been collected.
A．can
B．shall
C．will
D．may
