|
+ j2 ^2 h G+ \" e5 G
shall 应 指满足本规范必须遵从的强制性要求
, L. \4 s F: K" e7 x: e" R; @ Eshould 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5 y0 X& k& ] }! ^9 d
在否定证据当中不赞成某个措施但也不禁止 n: F/ g# ^% F. k! g
建议看一下:7 v8 f% O- ]: v0 N
http://bbs.angui.org/forum.php?m ... ghlight=shall%2Bmay
! q* }. n- r. t. F3 D( L; j" U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
/ w. ^2 M; L$ Y; Z* y
" d0 V, B3 c: L) M) D# {/ {single-core cable: no preferred colour scheme;% o8 J. r1 K2 T: M$ e
two-core cable: no preferred colour scheme;. T. n# F7 l, Z0 L& a# v2 J8 r
three-core cable: either green-and-yellow, blue, brown,
5 o- s0 _( P3 U# m0 uor brown, black, grey: S& C8 r3 {+ m! A
four-core cable: either green-and-yellow, brown, black, grey,
) B" f3 Y7 F" U \2 wor blue, brown, black, grey- r% N* |4 @9 J
five-core cable: either green-and-yellow, blue, brown, black, grey, O; ^% h9 m( P. [5 b
or blue, brown, black, grey, black.
) f* i' r, Q/ _2 a/ P8 ~: z |
|