问题描述：
Algae are very small _____ that live in the water .They grow fast when the water is ___ and rich
Algae are very small ____1_ that live in the water .They grow fast when the water is _2__ and rich in chemicals .
1
A trees
B flowers
C grass
D plants
2
A hot
B cold
C dirty
D clean
Algae are very small ____1_ that live in the water .They grow fast when the water is _2__ and rich in chemicals .
1
A trees
B flowers
C grass
D plants
2
A hot
B cold
C dirty
D clean
问题解答：
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