对于区分 can 和 can't 有困难的人士,曾经有个建议说 用be able to和be unable to来代替。我也曾经这样说过。2 `3 Z+ j7 q; D: n2 O6 ?) k" u
( `* W( E. \! E9 E" t但是要分场合。因为be able to实际的含义是有能力做。要是忽视这个含义,就可能出错。; l7 o r6 S j9 M; m" L
# ~; L' ~# M( H5 U) m2 `
比如,The rules can't be enforced. 要是给换一下,变成了 The rules are unable to be enforced. 这句话在逻辑上乱七八糟。因为rules本身没有什么能力去被执行。如果说 The manager was unable to enforce the rules. 逻辑上语法上都说得过去,可是被迫使用了主动语态,与原意不完全符合。" z! i$ l; [8 r" ^. H
4#雲吞9 ^0 x0 a2 i% ?+ y; }3 n
) V' A/ j; T8 A( Y/ b/ p+ Y3 e
下面是一个老外在网上出售仿真枪时作的说明:+ y4 z- o* V6 M
# P: {. M1 |+ ]& h7 LThis item cannot be made to fire and has never been capable of firing. The metal is not strong enough to hold a charge. For decorative purposes only. * i$ m; D0 Z+ ?( x