People often have this belief _______ development is bad for the environment, but this does not have to be true.
| A.whether | B.what |
| C.that | D.how |
In the 1950s in the USA, most families had just one phone at home, and wireless phones _______ yet.
| A. |
haven't invented |
B. |
haven't been invented |
| C. |
hadn't invented |
D. |
hadn't been invented |
If you don't understand something, you may research, study, and talk to other people _______ you figure it out.
| A. |
because |
B. |
though |
C. |
until |
D. |
since |
Many airlines now allow passengers to print their boarding passes online ______ their valuable time.
| A. |
save |
B. |
saving |
| C. |
to save |
D. |
saved |
Jane moved aimlessly down the tree-lined street, not knowing ______she was heading.
| A. |
why |
B. |
where |
C. |
how |
D. |
when |
______ birds use their feathers for flight, some of their feathers are for other purposes.
| A. |
Once |
B. |
If |
C. |
Although |
D. |
Because |