第12题: [单项选择]______ fairly recently, ______ solved, at least partially. A. Until… that this problem was B. It was until… that this problem was C. Not until… was this problem D. It was not until… when this problem was 参考答案:C 答案解析:[解析] until可以与not连用.表示“直到……(才)”。如果not until放到句首,其后面部分需部分倒装。根据这一点,可得出C为正确选项。
第13题: [单项选择]进步:退步 A. 黑色:白色 B. 领导:下级 C. 错误:正确 D. 高兴:痛苦 参考答案:C
第31题:[单选题]Thermal thunderstorm is caused by _______. A.heating imbalance of the earth’s surface B.the effect of the weather system C.the uplifting effect of the terrain D.the aclinic flow of temperature 参考答案:A