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C/ \5 x" H! r- ~shall 应 指满足本规范必须遵从的强制性要求
% [2 v8 T8 ^ oshould 应该 指在多个可能性当中,认为特别合适,但不排斥其它的可能性.或是优选一套措施,但不是要求.或是
6 g# Y4 Y( I7 Z在否定证据当中不赞成某个措施但也不禁止; W, J5 z5 X' [' T
建议看一下:( y3 M ]0 e* x0 k- Z1 J# H6 _
http://bbs.angui.org/forum.php?m ... ghlight=shall%2Bmay
# L, ^% I, o' c! h8 r$ e如果可以用别的颜色作为地线,那么,不排除让写标准的人承认,“棕、蓝”都可以用来作地线
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2 d( c8 Q4 m2 S( g- Tsingle-core cable: no preferred colour scheme;' |8 r3 E9 F7 o6 M( B- N
two-core cable: no preferred colour scheme;
3 I* P3 A" N& Uthree-core cable: either green-and-yellow, blue, brown,5 e6 B- o9 t; Y. H D4 p2 R9 ^" R
or brown, black, grey
% Q8 l: J( w$ t2 K* X( gfour-core cable: either green-and-yellow, brown, black, grey,) m9 Y j% c+ [$ c( I
or blue, brown, black, grey, h' a* J O. a8 N0 W8 o, q
five-core cable: either green-and-yellow, blue, brown, black, grey,# K9 f; J% E E8 T1 _8 g$ ~$ C* I
or blue, brown, black, grey, black.
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