---I’m sorry ,Mr.Wang. I _____ my homework at home .---That’s OK. But don’t forget ____ it to school tomorrow.
3D printers are still _____ expensive for most of us ______ afford.
The songs of the rock band sound ________.
Everyone passed the exam ________him. So he was sad.
I find ________ difficult to remember everything, though I’m still young.
It’s an ________well (井). Stay away from it.