参考答案

正确答案：A
解析：appalling表示条件之差使人感到吃惊。dreadful有类似的意义。如：My financial situation is dreadful．此句改用appalling也是可以的。bad，unpleasant和poor都可以跟condition搭配。因此可以说：They have been living under bad conditions for two years. They have been living under unpleasant conditions for two years．They have been living under poor conditions for two years．注意：appalling conditions蕴涵：bad(或unpleasant或poor)conditions. 但反向的蕴涵是不成立的。用句通俗的话说，是appalling conditions必定是bad(或unpleasant或poor)conditions，但是bad(或unpleasant或poor)conditions未必都是appalling conditions。也就是说，appalling跟bad，unpleasant和poor在意义上存在着明显的差别。注意：如果用bad或poor替换appalling，生成的都是错误的句子。