Diapers are 23 used by astronauts when they are outside the space shuttle, wearing a spacesuit.
答案：(D) still
still 意為「仍然」：當年為 Alan Shepard 想出的權宜辦法演變成尿布式太空廁所，直到今日太空人出艙穿太空衣時仍在使用；rather（相當）、almost（幾乎）、ever（曾經，多用於否定、疑問或完成式）語意都不合。
答對率 35%。
still 你一定認得，難在位置：本句是 Diapers are ___ used by astronauts，空格夾在 be 動詞與過去分詞之間。你熟悉的多半是「主詞＋still＋一般動詞」（She still lives here.）。規則其實很簡單：「still 放在 be 動詞之後、一般動詞之前」——are still used 正是標準位置。
本句自己沒有時間對照。回到段落開頭：Alan Shepard 的飛行原本只有十五分鐘、沒有如廁安排，後來延遲數小時，It was then decided that Alan Shepard should relieve himself in his space suit（於是決定讓他直接在太空衣裡解決）。這個權宜之計促成了第一具太空廁所——一種改良過的尿布。本句要說的就是：當年的權宜做法，到今天出艙時「仍然」在用。
rather（相當）修飾形容詞或副詞；almost（幾乎）語意不通；ever（曾經）多用於否定、疑問或完成式。
be still used（仍在使用）、no longer（不再）、relieve oneself（如廁）。
The first American space toilet was Alan Shepard's space suit. His flight was supposed to last only 15 minutes, so there was no provision made for him to relieve himself in the capsule. His flight, 21, was delayed for hours. It was then decided that Alan Shepard should relieve himself in his space suit, and continue with the mission as scheduled.
22 problem urged NASA to develop the first space toilet, a modified diaper. Diapers are 23 used by astronauts when they are outside the space shuttle, wearing a spacesuit.
As the flights grew longer, a new set of two collection bags was devised, 24 for liquid wastes and the other for solid wastes. Once used, the bags are sealed and stored for the flight back to the earth, 25 they are disposed of.