When ................... is not known. A. was the wheel ...

[ Adverb and Noun Clauses ]

When ………………. is not known.

A. was the wheel invented

B. the invention of the wheel

C. inventing the wheel

D. the wheel was invented

Select your answer:

Other quiz:

Tenses › View

Which sentence correctly emphasizes the activity of painting, not just the result?

A. I have painted three walls so far.

B. I have been painting all morning, and I’m exhausted.

C. I painted the room last weekend.

D. I have painted the kitchen blue.

Grammar › View

___________ lots of animals in the zoo.

A. There
B. There is
C. There are
D. There aren’t