结核性脓胸,肺出现结核病变,治疗方法是()
A.胸腔穿刺排脓
B.脓胸纤维板剥脱术
C.开放引流
D.闭式引流
参考答案:A
-_______students are there in your class, Mr Li? -Fifty.
A.How old
B.How much
C.How many
D.What
树木的幼年期有较大的遗传保守性。