判断以下句子的正误，把错误的更正出来。

判断以下句子的正误，把错误的更正出来。
1.I have never be to America,but he was there in 1996. （ ）
2.The boys have sharpend their pencils ten minutes ago. ( )
3.The teacher has just cleaned the blackboard. ( )
4.Have Tina turned on the television? ( )
5.Mr.Smith drove his car with a lamp-post. ( )