两闸瓦托中心至支柱中心距离差(L差)厂修限度不大于()。
A.3mm
B.5mm
C.10mm
D.15mm
参考答案:C
.----Who are those people gathering in front of the building?
-----A group __________ itself the youth volunteers.
A.calling
B.calls
C.called
D.to be called
心电图机的导联线都有屏蔽层,以防止电磁干扰。