题干
To enjoy the scenery, Irene would rather spend long hours on the train ___travel by air.
A：a
B：to
C：tha
D：while
答案(点此获取答案解析）
C
A：a
B：to
C：tha
D：while
的直线
将圆
分成两段弧，当其中的优弧最长时，