你想说“桌子上有一台电脑。”，你应这样说：________
A．There is a computer on the desk. B．There is a desk on the computer.
明明到你家做客，你对他表示欢迎，可以说：________
A．Welcome to my home. B．Hello, Mingming.
What are you ________？
A．do B．does C．doing
There ________ four armchairs and a new TV.
A．is B．are C．be
Can you clean the windows ________me?
A．at B．with C．to