转向系的修理要求是，球头销的球面和头部单边磨损超过（）mm，应焊修或更换。
A、1.0
B、1.5
C、2.0
D、5.0
参考答案：A
—_____ the population of the U.S.A. in 2005?
—It _____ about 296 million.
A. What is; is B. What was; was C.How many was; was
正规表达式的定义
