按正确的顺序排列下列对话。

A.Why do you like it?

B.What's your favorite subject,Dave?

C.I don't like it. It's so difficult.

D.Don't worry( 担心).I can help you.

E.My favorite subject is math.

F.Because it's interesting.What about you?

G.Thanks.

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胎传梅毒感染的途径是（）

A.梅毒父亲的精子传染

B.产道内有梅毒病灶

C.二期梅毒孕妇血行感染

D.孕期输入梅毒患者血液