磺胺抗菌原理是抑制菌体核酸合成的哪个环节()
A.二氢蝶酸合酶
B.二氢叶酸还原酶
C.一碳基转移酶的辅酶
D.依赖DNA的RNA多聚酶
E.DNA多聚酶
参考答案:A
They will not _____ even if they can’t win the match.
A.lose their hearts
B.lose their heart
C.lose the heart
D.lose heart
旅游者在学习过程中有哪3个基本环节?