The gravity on Mars is only about ________ of that on Earth.
| A．1/2 | B．2/3 | C．1/8 | D．3/8 |
Don't forget ________ your homework with you when you come to school.
| A．to bring | B．bringing | C．to take | D．taking |
He wants ____________some vegetables.
| A．buy | B．buying | C．to buy | D．buys |
I'm sorry ______ you.
| A．trouble | B．to trouble | C．troubling | D．troubled |
She went____________ her teacher.
| A．to see | B．looks | C．saw | D．seeing |
Robert often asks us ____________his Chinese, so his Chinese is much better than before.
| A．help him | B．to help him with | C．to help with | D．helps him with |