单项选择题
The reason (why) Jack (failed) to (attend) the lecture is (attend) he had a bad cold.
单项选择题 (It turned out) (why) the tiger (got out) of the cage because the man in charge (had forgotten) to lock it.
单项选择题 We kept our ______ all night to frighten the wolves.
单项选择题 He found ______ everybody know what had happened.
