You can come ______ on Tuesday _______ on Friday, but whichever you choose, please let me know.

It’s really nice _____ you. Thank you for your helping.[ ]

Shall I take you home after school?—No, thanks, Father will _______on his way home.

While I ___________ TV, the bell rang.

The air in Lanzhou is getting much _____ now than a few years ago .