在铁碳相图中，Ar3表好似高温奥氏体化的亚共析钢冷却时，（）开始析出温度。
A.铁素体
B.渗碳体
C.珠光体
D.贝氏体
参考答案：A
Most of the guests ________ to the wedding last week were his classmates and friends.
A．having been invited
B．to be invited
C．being invited
D．invited
腹腔干的主要分支是 ( )
A．腰动脉B．脾动脉C．肾动脉D．空、回肠动脉E．阑尾动脉
