Researchers calculated that there were 1,800 more suicides than would otherwise have been expected in the next four months.

【翻译】研究人员预测，在未来四个月内，自杀人数将比原本预期的要多出1800人。

【分析】网友的句子中含有more...than...结构，在此就不分析了。此外，than 引导的从句是一个“含蓄条件”虚拟语气句。这个含蓄条件就是otherwise，它的意思是：“要不然；与之相反”。本句的otherwise 就是“与之相反”的意思。由于是个比较句式，所以，这层意思可以不用翻译出来。

would have been expected 表示“与过去事实不符”：事实是比“原本预期的多出1800人，说明原来预期得不正确，与事实不一致”。

又如：

He reminded me of what I would otherwise have forgotten.

幸亏他及时提醒我，要不然我就忘了。

We must care for the weak who would otherwise fall by the wayside. 

我们要关心那些弱者, 不然他们会因失败而放弃努力的。

来自辞典例句

我把它们分别分成两句，就好理解了：

He reminded me of that; otherwise, I would  have forgotten it.

We must care for the weak, otherwise they would otherwise fall by the wayside.  

Researchers calculated that there were 1,800 more suicides than would otherwise have been expected in the next four months. 

参考译文：研究人员计算出/估计/推算，在接下来的四个月里，自杀人数比原本预计的要多出1800人.

(1)比较代词than后面省略与主句相同的部分，比较状语从句补充完整为：

than that there would be in the next four months would otherwise have been expected .如果把that从句用形式主语it替换就是下面的句子。

than it would otherwise have been expected that there would be in the next four months

(2)would otherwise have been expected 表示过去事实相反的一种假设。