在钢中含少量的不到（）的钒，能改善钢的焊接性能，增加钢的热强性和对蠕变的抗力。
A、0.3％
B、0.4％
C、0.5％
D、10％
参考答案：C
In recent years, TCP/IP has also begun to be used by telephone companies to provide faster, cheaper telephone (67)
A．transmitting
B．transmited
C．transfers
D．transmissions
