题目内容
【题目】They on (集中精力于) keeping their soil rich and free of disease.
【答案】focus / concentrate
【解析】focus / concentrate 固定词组：focus / concentrate on集中精力在---，故填focus / concentrate 。
练习册系列答案
相关题目
题目内容
【题目】They on (集中精力于) keeping their soil rich and free of disease.
【答案】focus / concentrate
【解析】focus / concentrate 固定词组：focus / concentrate on集中精力在---，故填focus / concentrate 。