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。: u! }! v5 D0 W5 A
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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。 ! ~# ~( j* X0 p. V" q8 N0 ]3 H( X0 i& D4 p7 M
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。) j, x- s. M7 T. e
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下面是一个老外在网上出售仿真枪时作的说明:9 j: W: W& L* R6 J8 C, L, C
% x% ~7 f% j* s, P$ L) O" @This 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. ( ]- t/ b3 x Q8 [$ e/ K; ]
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谨供参考。