题目

设实数，满足约束条件则的取值范围是（   ） A． B．          C．             D． 答案：D—Excuse me, could you tell me _____ later on? —Wait a minute. It is coming in ten minutes. [     ]A. if the next train arrives B. if the next train will arriveC. when the next train arrives D. when will the next train arrive