维生素B1又称（）。
A.硫胺素
B.尼克酸
C.叶酸
D.烟酸
E.核黄素
参考答案：A
— ______ those students Chinese, do you have to speak their language very often?
— No, they learn most when the class is taught in a foreign language. [ ]
A. To teach
B. Taught
C. Having taught
D. As to teach
甲的生长区位于（）
A.甲半月
B.甲板
C.甲床
D.甲母质
E.甲根
