— ________ are they staying? —Two days.
| A．How many | B．How often |
| C．How long | D．When |
Sally asked________________________.
| A．how could she get to the zoo. | B．how she can get to the zoo. |
| C．how she could get to the zoo. | D．where was the zoo. |
_______ the boy was walking down the street, the UFO landed.
| A．While | B．After | C．Before | D．until |
My friend has the same haircut __________ I do.
| A．as | B．like | C．seem | D．looks like |
Some scientists think that it may take ______ years to make robots look like people, and do the same things as us.
| A．hundreds of | B．two hundreds of | C．two hundreds | D． hundreds |
I think he is a student, ____？
| A．don’t I | B．isn’t he | C．is he | D．do I |