0.2L 0.2L
所以平衡前混合氣體的體積為1L+0.2L=1.2L,因此反應后氣體體積縮小率為16.7%。
1.(07年寧夏理綜·13)一定條件下,合成氨氣反應達到平衡時,測得混合氣體中氨氣的體積分數為20.0% ,與反應前的體積相比,反應后體積縮小的百分率是
A.16.7% B.20.0% C.80.0% D.83.3%
答案:A
解析:設達到平衡后混合氣體的體積為1L,則其中生成的氨氣的體積為1L×20.0%=0.2L。則根據反應的方程式有:
N2+3H22NH3
△V
1 3 2 2
45.The boss praised the young man for his hard work, though he ____ experience. A. is lack of B. is lacking inC. lacks of D. is lacking of
此題答案選b,be lacking in是習語,意為“缺乏”,其后通常接experience, frankness, courage等抽象名詞。選a是錯誤的,因為lack可用做名詞和動詞,但不用做形容詞;選c是錯誤的,因為lack用做動詞時,它是及物動詞,其后不用介詞(注:用做名詞的 lack后可接介詞of);選d是錯誤的,因為沒有be lacking of這個搭配。
44.An awful accident, however, _____occur the other day. A. does B. did C. has to D had to
此題正確答案應選B,句末的the other day意為“前幾天”,所以句子應用過去時態,而選項D填進去不合題意,故選B。此句有兩個難點:一是句中插有however一詞,分散了同學們的注意力;二是所填選項B為強調用法。
43.It is what you do rather than what you say______matters. (2005天津卷)
A. that B. what C. which D. this
分析:答案是A。由語境和句子結構可知,該句為強調句型,被強調部分是由rather than連接的并列主語從句擔當。
42.Mom is coming. What present _________for your birthday? (2005福建卷)
A. you expect you have got B. you expect has she got
C.do you expect she has got D. do you expect has she got
分析:答案是C。由語境和句子結構得知,后一句為帶插入語do you expect的特殊疑問句,插入語后面內容應視為賓語從句且采用陳述語序。
41.--Is that the small town you often refer to?(2005福建卷)
--Right,just the one____ you know I used to work for years.
A. that B. which C. where D. what
分析:答案是C。由語境和句子結構可知,you know為插入語,將其去掉更易看出the one是指the small town,因此該空應該填where引導定語從句。
40. -Have you ever seen Peter recently ?
-Yes . He _____ me to ask you how you _____ along with your new job these days .
A. has asked ; have been getting B. asked ; were getting
C. often asks ; are getting D. asked ; are getting
答案是D項。問方的所問被完整地給出:"近來你見到彼德了嗎?"答方給予的第一個答復是肯定的,那末后面解釋他一彼德見面時所做事肯定是過去的事,因此第一個空應該使用asked。第二空是否受asked的制約,要由離第二個空白處最近的動詞決定,離它近的是動詞不定式to ask,據此根據句意,第二個空白處應該使用現在進行時。
39. Mary ______ to see you . She _____ for you downstairs at the moment .
A. has come ; is waiting B. came ; is waiting C. has come ; waited D. came ; was waiting
答案是A項。思考這道題時應該使用逆向思維,即先考慮第二個空白處的選項,再考慮第一空白處的答案。因為第二句中交代了一個重要的時間狀語:at the moment (現在),因此應毫不猶豫地選擇is waiting這一現在進行時的時態。據此第一句的句意也就隨之清晰起來?quot;瑪麗已經到這兒來看望你"很明顯對表示對現在造成影響的動作要使用現在完成時態。
38. A man does not know the difficulty of anything _____ he does it personally .
A. although B. if C. because D. unless
答案是D項。連詞unless本身具有否定意義:if … not,引導的是否定的條件句,這種否定的條件句從反面來表達強烈的語氣,一些語法學家稱它為"反面的唯一條件句"又如:One cannot master a foreign language well unless he studies it hard . (不下苦功夫,是學不好的一門外國語的。)
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