润滑脂中加入少量（）可以大大提高润滑性，有效降低机械磨损。
A.石墨
B.聚四氟乙烯
C.二硫化钨
D.二硫化钼
参考答案：D
根据句意及首字母提示完成句子。
1. Go to the l____________ to read a book.
2. It was a birthday gift f____________ my mom.
3. Is the office f____________ from here?
4. Let's go to a r____________ to eat ice cream.
5. I listen to the r____________ in my bed.
6. These new slippers are just r____________.
临床上用超声测量胎头双顶径，提示胎儿成熟的标准是
A．双顶径≤8.5cmB．双顶径≥8.5cmC．双顶径≥9.5cmD．5.5cm≤双顶径≤8.5cmE．双顶径≥6.5cm
