There is a three - feet-high fence in front of the house.
結(jié)構(gòu)分析如下：
isfence 主謂一致,正確
in front of 在.前面,正確（注意：in the front of是在.內(nèi)部的前面,例：The teacher is in the front of the classroom. ）
錯誤之處：
three-feet-high 復(fù)合形容詞前置修飾名詞（fence）,需要+連字符,但是feet須改為單數(shù)形式foot
正確形式為：
There is a three-foot-high fence in front of the house.