地球的表面积是（）
A.5.1亿平方千米
B.5.1亿千米
C.5.1亿立方千米
D.5.1平方千米
参考答案：A
请你用所给词的适当形式完成下列句子。
1. Here are some things they have learned from ______(scientist ) studies.
2. Sunglasses are used for _____ (keep) out the sun.
3. The students are ______ (confuse) about the ______ (confuse) problem.
4. I’m considering _____ (study) in Beijing or Shanghai.
5. I felt _______(embarrass) when everyone looked at me.
情况是这样的，昨天晚上单位一同事因胃痛急诊进院，今早出院。不知道夜间急诊就业能否进行医保联网结算？
