第7题: [单项选择]All flights ______because of the snowstorm, many passengers could do nothing but take the train. A. had been canceled B. have been canceled C. were canceled D. having been canceled 参考答案:D 答案解析:该题为“逻辑主语+doing”构成主语独立结构,表示原因。
第8题: [单项选择]眼球壁包括() A. 角膜-巩膜-虹膜-视网膜 B. 结膜-角膜-巩膜-视网膜 C. 角膜-巩膜-葡萄膜-视网膜 D. 角膜-巩膜-睫状体-视网膜 E. 角膜-巩膜-脉络膜-视网膜 参考答案:C 答案解析: