制动缸活塞和压板裂纹时更换，有漏泄沟者不得堵塞。
参考答案：对
Without ______ a word, he went out of the room ______ the light on. [ ]
A. say, for
B. saying, but
C. to say, put
D. saying, with
选择素分子识别的配体是（）
A.CD15s（sLex）
B.CD21
C.CD31
D.CD44
E.钙粘蛋白
