原式=10a-3ab+30a-a-2ab=40a-5ab-a.
选择与句中划线部分意思相同或相近的选项。
The U.S. is south of Canada. [ ]
A. Canada is north of the U.S.
B. The U.S. is in the south of Canada.
C. Canada is far from the U.S.
D. Canada is east of the U.S.
在孕妇腹壁上听诊,与母体心率相一致的音响是()
A.胎心音
B.子宫杂音+腹主动脉
C.脐带杂音
D.胎动音
E.肠蠕动音