在我国半干旱草原区,植被破坏后经过足够的时间都能形成森林群落。

在我国半干旱草原区,植被破坏后经过足够的时间都能形成森林群落。

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During the past two decades, research has __________ our kno

During the past two decades, research has __________ our knowledge of daydreamin

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We have greatly __________ the procedure according to the ch

We have greatly __________ the procedure according to the chairman's suggestion.

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The medicine is on sale everywhere. You can get it at ______

The medicine is on sale everywhere. You can get it at ________ chemists.A.each B

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