在职攻硕英语考试

【单选题】 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

网考网参考答案：D
网考网解析：
[解析] 该题为“逻辑主语+doing”构成的主语独立结构，表示原因。 查看试题解析出处>>