首先 挑个错,you have understand 是没有的东西,应该是 you have understood. (完成式)
或者就用现在式,you understand.
答案选A, Once you have understood this rule, you have no further difficulty.
(你一旦明白了这个规则) (就没有更多问题/困难了.)
其他几个选项要用的话,要嘛改句子,要嘛意思就变样了：
unless=除非...否则
unless you have understood this rule, you have no further difficulty.
除非你明白这个规则,否则是不会有问题的 (规则懂得越多问题就越多?!)
only=只有、唯有
only WHEN you have understood this rule will you (对,这个顺序) have no further difficulty
唯有当你了解...的时候,才不会有更多的难题 (意思对了,但太复杂了,有点彆扭)
until=直到...(的时候)
until you have understood this rule, you will have no further difficulty.
一直到你明白了这条规则为止 都不会有更多难题 (所以大家最好不要明白... (^_^|||)
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老实说 在下觉得这整个句子都有点怪...
一般要不是说 once you have understood.you will have. ( =完成式 後面跟未来式)
你一旦了解"了以後" 就"不会" 再有问题了
要不就是 once you understand.you have. ( =全部现在式)
你一旦了解就没问题了
再不然就是: once you understand.you will have. ( =前半现在,後半还是一样用未来式)
第一个和最後一个都比较顺.
我讲了一堆,好像有点混乱.总之希望对你有些帮助、欢迎更多的问题! (^_^ )