《由标点符号引起的错句》里谈到不完整和无休止的句子(run-on sentences)时，我曾指出句子不可以一个接一个，只有逗号，没有句点。

和不完整的句子有些相似的是不完整的结构(incomplete constructions)。这种结构属高层次情况，偶尔出现，也不奇怪，但是若能避免，那就更好了。

什么结构是不完整的呢?原因何在?

顾名思义，不完整结构就是一个结构中欠缺了某个语言成分，以致不合规格，导致句法上的困惑。例如下列这个句子便出现结构不完整的瑕疵：

“Thank you for your continuous interest and support for our magazines.”

这里要感谢的事有二：对杂志的兴趣与支持。

英译中不成问题，但“interest”后面要加“in”才可以和“support for”对称。缺少了“in”，这结构便不完整了。像这种情形，最好将两件事分开，因此，上面那句话可以改写如下：

“Thank you for your continuous interest in our magazines and your strong support for them.”

同样的，下面三个结构不完整的句子，也要作适当的调整，使句子的意思清楚易解：

① Sam is good and successful in painting.

② The Chairman’s argument was sound and adopted without any discussion.

③ Professor Chen has taught in many universities, London University and Harvard University.

在①句里，必须在“good”后面补上漏掉的介词“at”。在②里的第二个并列句的“……adopted……”是个被动式，前面的助动词“was”不可省。③里的“many universities”包括了所提的两所，所以要在它们前面加“including”或“such as”，才合逻辑。不然全句要改写如下：

“Professor Chen has taught in London University, Harvard University and many other universities.”

上面句子不是忽略了介词，便是少去了助动词等。还有些不完整的结构是发生在比较句中。例如：

④ Many buildings in Singapore are as modern as any other city.

这里把“buildings in Singapore”和“any other city”相比，逻辑何在?应该调整为建筑物间的比较才对：

“Many buildings in Singapore are as modern as those of any other city.”

⑤ The athlete is as strong, if not stronger than, the wrestler.

英语里的“as……as……”是连用的，因此这句要改为“The athlete is as strong as, if not stronger than, the wrestler.”但是为了紧凑起见，全句可改写如下：

“The athlete is as strong as the wrestler, if not stronger.”

⑥ Japanese cars use less petroleum.

这句话的小毛病是，另外一样被比较的东西不详，要补上使结构完整。

“Japanese cars use less petroleum than European cars.”