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。' n+ `: |# G/ ]7 j7 v- n. J M5 S
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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。6 H3 d& e) v, h" o B8 G: h
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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。( N! t, }: p4 O: ]( e
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如果我理解有误,请大家指正。
1 f1 V; Z8 n* k! l/ |+ ?下面是一个老外在网上出售仿真枪时作的说明: 9 q9 ]1 u+ j* Y2 ?% T9 P7 s: s# B3 |4 J/ a* z3 j
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. ! H4 K* T2 a) `4 i; Y* B$ y- T