雷诺综合征典型的发病过程是当肢端受到不良刺激后，手指肤色先变_____，继为_______，而后______。
参考答案：苍白、青紫、潮红
Sometimes parents’ control of young kids will be thought to be such an invisible rope, with which to tie them tightly, that they _____ tried to cut it.
A．thoroughly
B．visually
C．desperately
D．appropriately
下列关于有机化合物的说法正确的是( )
A．用碳酸钠溶液鉴别乙醇、乙酸和乙酸乙酯
B．戊烷（C5H12）有两种同分异构体
C．乙烯、聚氯乙烯和苯分子中均含有碳碳双键
D．糖类、油脂和蛋白质均可发生水解反应
