The students asked _________________.

A．when can they surf the Internet in class

B．when could they surf the Internet in class

C．when they could surf the Internet in class

D．when they can surf the Internet in class

在我国实施辅助生殖技术，违背卫生部制定的伦理原则的是（）。

A.使用捐赠的精子

B.使用亲属代孕

C.使用卵泡浆内单精注射

D.使用捐赠的卵子

E.使用捐赠的胚胎