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【单选题】
按酸碱质子理论,下列物质中既是酸,又是碱的是
A.
CO 3 2-
B.
HCl
C.
NH 4 +
D.
HCO 3 -
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举一反三
【单选题】—Why didn't Tom attend the meeting yesterday? —He ____ Beijing.
A.
has gone to
B.
had gone to
C.
went to
D.
had been to
查看完整题目与答案
【单选题】Tom didn’t attend the meeting, ________ we expected.
A.
where
B.
that
C.
as
D.
what
查看完整题目与答案
【单选题】设计一般闭式齿轮传动时,计算接触疲劳强度是为了避免( )
A.
齿面胶合
B.
齿面磨粒磨损
C.
齿面点蚀
D.
轮齿折断
查看完整题目与答案
【单选题】维生素和无机盐的缺乏会引起入体患多种疾病。下列有关无机盐、维生素缺乏症的表述中，正确的是( )。 ①缺乏含钙的无机盐易患佝偻病、骨质疏松症 ②缺乏含磷的无机盐易患地方性甲状腺肿 ③缺乏含锌的无机盐易造成生长发育不良，味觉发生障碍 ④缺乏维生素A易患神经炎、脚气病 ⑤缺乏维生素C易患坏血病，抵抗力下降
A.
①③⑤
B.
①②④
C.
②③④
D.
②④⑤
查看完整题目与答案
【简答题】Tom didn't attend the meeting,___we expected.
查看完整题目与答案
【单选题】Tom didn't attend the meeting, ( )we had expected.
A.
where
B.
that
C.
as
D.
what
查看完整题目与答案
【单选题】—Why didn't Tom attend the meeting yesterday ? —He ____ Beijing . A . has gone to
A.
． has gone to
B.
． had gone to
C.
． went to
D.
． had been to
查看完整题目与答案
【单选题】以下关于维生素缺乏及过多症的说法中,错误的是()。
A.
犬.猫出现维生素C.维生素E缺乏时,即使饲料中含有维生素A,也会由于维生素A吸收效率下降而出现维生素A缺乏症;
B.
长期大量饲喂动物肝脏,易引起维生素A过多症或中毒,病犬表现为角膜增厚.呈云雾状.皮肤干燥.生殖功能降低;
C.
B族维生素在体内不易蓄积,故临床上一般不出现B族维生素过剩或中毒,相反,出现较多的是B族维生素缺乏症;
D.
动物多晒太阳,可以有效防治维生素D的缺乏。
查看完整题目与答案
【判断题】维生素C具有多种生理功能，缺乏时会引起多种症状，其中最明显的是坏血病症状。
A.
正确
B.
错误
查看完整题目与答案
【单选题】Why didn't Tom attend the meeting yesterday?
A.
has gone to
B.
had gone to
C.
went to
D.
had been to
查看完整题目与答案
相关题目：
【单选题】—Why didn't Tom attend the meeting yesterday? —He ____ Beijing.
A.
has gone to
B.
had gone to
C.
went to
D.
had been to
查看完整题目与答案
【单选题】Tom didn’t attend the meeting, ________ we expected.
A.
where
B.
that
C.
as
D.
what
查看完整题目与答案
【单选题】设计一般闭式齿轮传动时,计算接触疲劳强度是为了避免( )
A.
齿面胶合
B.
齿面磨粒磨损
C.
齿面点蚀
D.
轮齿折断
查看完整题目与答案
【单选题】维生素和无机盐的缺乏会引起入体患多种疾病。下列有关无机盐、维生素缺乏症的表述中，正确的是( )。 ①缺乏含钙的无机盐易患佝偻病、骨质疏松症 ②缺乏含磷的无机盐易患地方性甲状腺肿 ③缺乏含锌的无机盐易造成生长发育不良，味觉发生障碍 ④缺乏维生素A易患神经炎、脚气病 ⑤缺乏维生素C易患坏血病，抵抗力下降
A.
①③⑤
B.
①②④
C.
②③④
D.
②④⑤
查看完整题目与答案
【简答题】Tom didn't attend the meeting,___we expected.
查看完整题目与答案
【单选题】Tom didn't attend the meeting, ( )we had expected.
A.
where
B.
that
C.
as
D.
what
查看完整题目与答案
【单选题】—Why didn't Tom attend the meeting yesterday ? —He ____ Beijing . A . has gone to
A.
． has gone to
B.
． had gone to
C.
． went to
D.
． had been to
查看完整题目与答案
【单选题】以下关于维生素缺乏及过多症的说法中,错误的是()。
A.
犬.猫出现维生素C.维生素E缺乏时,即使饲料中含有维生素A,也会由于维生素A吸收效率下降而出现维生素A缺乏症;
B.
长期大量饲喂动物肝脏,易引起维生素A过多症或中毒,病犬表现为角膜增厚.呈云雾状.皮肤干燥.生殖功能降低;
C.
B族维生素在体内不易蓄积,故临床上一般不出现B族维生素过剩或中毒,相反,出现较多的是B族维生素缺乏症;
D.
动物多晒太阳,可以有效防治维生素D的缺乏。
查看完整题目与答案
【判断题】维生素C具有多种生理功能，缺乏时会引起多种症状，其中最明显的是坏血病症状。
A.
正确
B.
错误
查看完整题目与答案
【单选题】Why didn't Tom attend the meeting yesterday?
A.
has gone to
B.
had gone to
C.
went to
D.
had been to
查看完整题目与答案