为阻断仲胺和亚硝酸盐合成亚硝胺，应同时给于()。
A.维生素B12
B.叶酸
C.维生素B2
D.维生素C
参考答案：D
Have you determined_________?
A．next to do what
B．what to do next
C．how to do next
D．next how to do
