21.The little boy won't go to sleep ________ his mother tells him a story.

　　A. or B. unless

　　C. but D. whether

　　[解析]句意：除非媽媽給他講故事，否則小男孩就不去睡覺。or 或者，否則;unless 除非;but 但，除……之外;whether 是否。根據(jù)語境可知，這里用 unless 表示“除非……否則……”。

　　[答案]B

　　22.The school rules state that no child shall be allowed out of the school during the day, ________ accompanied by an adult.

　　A. once B. when

　　C. if D. unless

　　[解析]句意：學校制度規(guī)定：在白天，除非有大人陪同，否則不允許孩子走出校園。A：一旦;B：當……的時候;C：如果;D：除非。

　　[答案]D

　　23.________ you may have, you should gather your courage to face the challenge.

　　A. However a serious problem

　　B. What a serious problem

　　C. However serious a problem

　　D. What serious a problem

　　[解析]句意：無論你的問題有多嚴重，你都應該鼓起勇氣來接受挑戰(zhàn)。分析題干可知逗號前是讓步狀語從句，what 不能用來引導狀語從句，所以排除B、D兩項;however+adj.+a/an+單數(shù)名詞=whatever+a/an+adj.+單數(shù)名詞，故C項正確。

　　[答案]C

　　24.________ our manager objects to Tom's joining the club, we shall accept him as a member.

　　A. Until B. Unless

　　C. If D. After

　　[解析]句意：我們愿意接受湯姆為我們的成員，除非經(jīng)理反對他加入本俱樂部。選項中的四個詞都可以連接從句。但是這里存在條件關系，故排除A(直到)和D(在……之后)，而語境存在否定條件，故排除C(如果)。

　　[答案]B

　　25._______ they decide which college to go to, students should research the admission procedures.

　　A. As B. While

　　C. Until D. Once

　　[解析]句意：一旦學生們決定了要上哪所大學，他們就應該研究申請此大學的程序了。as 當……時，由于;while 當……時，盡管;until 直到;once 一旦。根據(jù)句意選擇D項。

　　[答案]D

　　26.John thinks it won't be long ________ he is ready for his new job.

　　A. when　　　B. after C. before　　　D. since

　　[解析]句意：約翰認為不久他就能為他的新工作做好準備。本題考查句式 It won't be long before...，表示“過不了多久就……”。注意以下句子的區(qū)別：

　�、買t is three years since he left.

　　②It was three years before he left.

　�、跧t was three years ago that he left.

　�、躀t was three o'clock when/before he left.

　　[答案] C

　　27.—Our holiday cost a lot of money.

　　—Did it? Well, that doesn't matter ________ you enjoyed yourselves.

　　A. as long as B. unless

　　C. as soon as D. though

　　[解析]句意：——我們這次度假花了很多錢�！�—是嗎?沒關系，只要你們玩得高興就行。本題考查連詞的用法。as long as 只要;unless 除非;as soon as 一……就;though 盡管，雖然。

　　[答案]A

　　28.The girl had hardly rung the bell ________ the door was opened suddenly, and her friend rushed out to greet her.

　　A. before B. until

　　C. as D. since

　　[解析]句意：這個女孩剛一按門鈴，門就突然打開了，她的朋友沖出來迎接她。本題考查固定句型 hardly... when/before...，意為“一……就……”。

　　[答案]A

　　29.The engineers are so busy that they have zero time for outdoor sports activities, ________ they have the interest.

　　A. wherever B. whenever

　　C. even if D. as if

　　[解析]句意：工程師們如此忙碌，以至于沒時間做戶外活動，即使他們對做戶外活動很感興趣。本題考查連詞。even if 即使，引導讓步狀語從句。wherever 無論什么地方;whenever 無論什么時候;as if 好像。

　　[答案]C

　　30.Just use this room for the time being, and we'll offer you a larger one ________ it becomes available.

　　A. as soon as B. unless

　　C. as far as D. until

　　[解析]句意：暫時用這個房間吧，一有可能，我們就會給你提供一個大點的房子。本題考查連詞。as soon as 一……就……，引導時間狀語從句。unless 除非;as far as 遠到，至于;until 直到。

　　[答案]A

　　31.The old man asked Lucy to move to another chair ________ he wanted to sit next to his wife.

　　A. although B. unless

　　C. because D. if

　　[解析]句意：那位老人請 Lucy 換坐另一把椅子，因為他想挨著他妻子坐。本題考查狀語從句引導詞。由句意分析前后為因果關系，所以選 because。A盡管;B除非;C因為;D如果。

　　[答案]C

　　32.The little girl who got lost decided to remain ________ she was and wait for her mother.

　　A. where B. what

　　C. how D. who

　　[解析]句意：那個迷路的小女孩決定待在原地等她的母親。where 引導地點狀語從句。

　　[答案]A

　　33.—Shall we have our picnic tomorrow?

　　—________ it doesn't rain.

　　A. Until B. While

　　C. Once D. If

　　[解析]句意：——明天我們去野餐好嗎?——如果不下雨的話。until 直到……時間;while 當……的時候;once 一旦……(就……);if 如果……

　　[答案]D

　　34.My parents don't mind what job I do ______ I am happy.

　　A. even though B. as soon as

　　C. as long as D. as though

　　[解析]句意：我的父母不在乎我從事什么樣的工作，只要我高興就好。本題考查狀語從句。as long as(=so long as)引導條件狀語從句，意為“只要”。as soon as 一……就……;even though 雖然，盡管;as though 好像。

　　[答案]C