17. (2026 扬州一模) —When will the Shanghai-Nanjing-Hefei High-speed Railway in our city at the speed of 350 kilometers per hour be in service?
— 2027. Two fifths been completed smoothly so far.
A.Until; has B.Until; have
C.Not until; has D.Not until; have
18.(2026连云港二模) 我们直到老师进来才开始讨论。
We ______ begin our discussion ______ the teacher came in.
19. [微写作]很多人直到生病了才意识到健康的重要性。

【用法】 not...until...意为“直到……才……”，主句中的谓语动词多为 arrive、come、go、leave 等表示位置移动或短暂动作的词。until 后跟从句时，表示主句的动作直到 until 从句表达的时刻才发生；until 作介词后跟时间表达时，表示句子的动作直到 until 后的时间点才发生。
· We did not leave the library until he came. 直到他来了之后，我们才离开图书馆。
【拓展】 until 用于肯定句中，后跟从句时，表示主句的动作延续到从句所表达的动作发生为止，意为“直到”。此时主句中的谓语动词多为 work、continue、remain、stay、wait 等表示持续动作的动词。
· She stood there until he passed out of sight. 她站在那儿直到再也看不见他。

17. C 18. didn't; until 19. Many people don't realize the importance of health until they fall ill.(答案不唯一)

20.(2026无锡二模) (任何) colour you pick, just keep your mind on what you are doing.
21. Whatever difficulties they met, they tried their best to finish their tasks.(多样句式升格)
= difficulties they met, they tried their best to finish their tasks.
22. 微写作 春节期间,无论人们身在何处,都会设法回家与家人团聚并一起庆祝春节。
During the Spring Festival, , , to reunite with their families and celebrate the Spring Festival together.
【用法】 no matter where 意为“无论哪里”,引导让步状语从句,此时相当于 wherever。
· No matter where you go in the world, don't forget your motherland. 无论你走到世界的哪个角落,都别忘了你的祖国。
【考点联动】 其他类似的词汇

20. Whatever/No matter what 21. No matter what 22. no matter where/wherever people are; they'll manage to go back home