составить предложения в present perfect simple

Lesson hasnt started yet

Teacher has already written on the board

Joe and Tim have just came into class room

Tonny havent finished getting

Cristina already have opened book

Dave have dropped pen

He hasnt pick it up yet

1. the lesson has not started yet

2. the teacher has already written on the board

3. Joe and Tom have just come into the classroom

4 Tony has not finished getting the books ready

5 Christine has already opened the book