Q26:

The Organization of Petroleum Exporting Countries (OPEC) had long been expected to announce a reduction in output to bolster sagging oil prices, but officials of the organization just recently announced that the group will pare daily production by 1.5 million barrels by the beginning of next year, but only if non-OPEC nations, including Norway, Mexico, and Russia, were to trim output by a total of 500,000 barrels a day.

1. year, but only if non-OPEC nations, including Norway, Mexico, and Russia, were to trim output
2. year, but only if the output of non-OPEC nations, which includes Norway, Mexico, and Russia, is trimmed
3. year only if the output of non-OPEC nations, including Norway, Mexico, and Russia, would be trimmed
4. year only if non-OPEC nations, which includes Norway, Mexico, and Russia, were trimming output
5. year only if non-OPEC nations, including Norway, Mexico, and Russia, trim output

   Answer: E

想问说C为啥不对尼？

我觉得C的问题是

1.没有理由的被动语态不选，by是被动的标志

2.还有OG解释有这么一句话 the if clause in B must take should rather than would  是虚拟语气所以觉得E这里是省略了should个人意见，继续讨论

同意~好像像这种情况下面B句的确通常都不用would~

我的理解是：

划线部分前面的部分 the group will pare daily production by ...使用的是主动形式，划线部分only if 后面也使用主动形式会让这两部分更协调。

我单纯的以为主句将来时态，if从句用现在时态。不知道是否正确.