1 The box is so heavy that he can't lift it .
The box is too heavy for him to lift.
The box is not light enough for him to lift .
2 The room is so dirty that they can't live in it.
The room is too dirty for them to live in.
The room is not clean enough for them to live in .
3 The pencil is so short that he can't write with it.
The pencil is too short for him to write with .
The pencil is not long for him to write with .