There is _____ “u” and _______ “s” in the word “us”.
| A．an, a | B．a, a |
| C．an, an | D．a, an |
He lives on ________ floor in that building.
| A．three | B．third | C．the third | D．the three |
You are not supposed to get off the bus ________ it stops.
| A．though | B．while | C．until | D．because |
My teacher encouraged me ________ more confident.
| A．am | B．is | C．be | D．to be |
The taxis in this city ________ in the same color. You can see them every day.
| A．are | B．has | C．is | D．have |
I don’t know her. She is ________ my classmate nor my friend.
| A．either | B．neither | C．both | D．none |