Để chứng minh trong phân tử fructozo có nhiều nhóm hiđroxyl, người ta cho dung dịch fructozo phản ứng với
A.\[AgN{O_3}\] trong dung dịch \[N{H_3}\], đun nóng
B.Kim loại Na
C.\[Cu{\left( {OH} \right)_2}\] ở nhiệt độ thường
D.\[Cu{\left( {OH} \right)_2}\] trong NaOH, đun nóng

Chất nào trong số chất sau có khả năng tham gia phản ứng tráng gương?
A.Saccarozơ.
B.Xenlulozơ.
C.Fructozơ.
D.Tinh bột.

Choose the answer among A, B, C, D to complete each of the sentences below:
I believe that everyone has had ________ experiences in their life.
A.acceptable
B.observable
C.reflexible
D.memorable

Choose the answer among A, B, C, D to complete each of the sentences below:
Neil Armstrong, an American ______, was the first man to step on the moon's surface.
A.astronaut
B.astronomer
C.cosmonaut
D.scientist

Choose the answer among A, B, C, D to complete each of the sentences below:
We have bought extra food ______ our friends stay to dinner.
A.as long as
B.provided
C.if
D.in case

Choose the answer among A, B, C, D to complete each of the sentences below:
The _______ of these toxic substances into the environment is potentially devastating.
A.delivery
B.research
C.distribution
D.release

Choose the answer among A, B, C, D to complete each of the sentences below:
_____ test was given, our class leader managed to get good marks.
A.However
B.Wherever
C.Whatever
D.Whenever

Choose the answer among A, B, C, D to complete each of the sentences below:
Their efforts were much ______ when they won 2 gold, medals in bodybuilding and billiards.
A.expended
B.required
C.considered
D.appreciated

Choose the answer among A, B, C, D to complete each of the sentences below:
I am pleased to _______ the winner of the final competition. It's Group B
A.recite
B.appoint
C.announce
D.explain

Choose the answer among A, B, C, D to complete each of the sentences below:
Our field _____ have performed very well.
A.artists
B.sportmen
C.athletes
D.specialists