对本初子午线的下列说法正确的是[ ]
A．是东西半球的界线
B．是国际日期变更线
C．自成圆圈
D．是零度经线
答案：D
航天员（）实现了我国航天史上第一次太空行走。
A.杨利伟
B.翟志刚
C.聂海胜
The nurse is administering magnesium sulfate to a client with preeclampsia. The nurse explains to the client that this drug is given for which of the following reason
A．To prevent seizures.
B．To reduce blood pressure.
C．To slow the process of labor.
D．To increase diuresis.
