小细胞低色素性贫血的主要发病机制（）
A.产生血小板抗体
B.骨髓造血功能衰竭
C.机体免疫功能缺陷
D.铁缺乏
E.凝血因子缺乏
参考答案：D
The coal miners________in the coal mine for 10 hours before we came to their rescue.[ ]
A. had trapped
B. had been trapping
C. had been trapped
D. would have been trapped
（）不属于新彩颜料的常用辅助性漆加物。
A.乳香油
B.香油
C.桦香油
D.樟脑油
