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shall 应 指满足本规范必须遵从的强制性要求
, M1 x( s- y. @7 C/ ~- Dshould 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
( R: k( f+ G* F) w! ^5 \( ^$ j在否定证据当中不赞成某个措施但也不禁止0 \- W# w8 ?: |* C; F
建议看一下:
/ ^4 L+ m% f8 D0 m# zhttp://bbs.angui.org/forum.php?m ... ghlight=shall%2Bmay
9 z8 w4 D$ Z1 }! u* t# s }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; b% }- C2 Y/ n0 l7 u' L+ I
8 e7 C3 Z3 A7 tsingle-core cable: no preferred colour scheme;2 D8 d- F' s# J, C9 t, B
two-core cable: no preferred colour scheme;
, i6 d* r; q' d& n( rthree-core cable: either green-and-yellow, blue, brown,! V% u) s! a5 M2 s2 g
or brown, black, grey; o2 f( L3 G# h' ]9 U- |% @! f( [ F
four-core cable: either green-and-yellow, brown, black, grey,# C. P& W8 t' T. g3 H' C: }
or blue, brown, black, grey
* l1 U, E% q# L* H$ Jfive-core cable: either green-and-yellow, blue, brown, black, grey,
1 j7 E J. [$ T: x; Oor blue, brown, black, grey, black.
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