一、单选题 1. Tom _____ his flight by twenty minutes. A. missed B. caught C. took 2. He checked in late, _____ he didn ’ t get a window seat. A. that B. so that C. until 3. I ’ d like to have an economy _____. A. service B. class C. kind 4. She didn ’ t leave for the airport ____ you came. A. unless B. until C. if 5. Please come to _____ your ticket at the booking office. A. check up B. pick up C. turn up.