上贝氏体显微组织特征呈（）。
A.羽毛状
B.黑色针叶状
C.片层状
D.粒状
参考答案：A
Mary worked here as a ____ secretary and ended up getting a full-time job with the company.
A．pessimistic
B．temporary
C．previous
D．cautious
自主维修的七大主要实施步骤是哪些？
