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) f% Q( E1 S) G" h* `# D2 G8 xshall 应 指满足本规范必须遵从的强制性要求# F: P) H" ^ A J! I7 o
should 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3 c4 ^& B7 [. A, d) F: x! ]+ l% A
在否定证据当中不赞成某个措施但也不禁止
7 L) q6 d$ c( Y& C4 I建议看一下:
5 x( I" t0 e7 j2 v6 w8 E) T; lhttp://bbs.angui.org/forum.php?m ... ghlight=shall%2Bmay
" C. t0 K+ P6 F( T, |: b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" b6 o. g6 b) [! v
9 ~" c( A& `# @! u1 h* }single-core cable: no preferred colour scheme;
/ _$ p/ V+ E: u: Ntwo-core cable: no preferred colour scheme;6 Y$ R6 \) R- Z% M! ]" z/ b
three-core cable: either green-and-yellow, blue, brown,! g9 W% U0 \4 t8 H
or brown, black, grey; N: Z. P+ r. i, \2 ^
four-core cable: either green-and-yellow, brown, black, grey,
& \% Z$ ?! @$ K, \3 d5 A1 I% Mor blue, brown, black, grey
- ?1 K7 n: t8 \$ k& g- Efive-core cable: either green-and-yellow, blue, brown, black, grey,
" R" o/ ]* o) [2 n: E0 ?( wor blue, brown, black, grey, black.
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