part of speech for thought is (thinking).
Answer:
active voice
Explanation:
the subject of the sentence is being acted upon
if this isn't right I'm sorry but I think its right
The correct answer is were.
Since English grammar has this thing called the sequence of tenses, which means that if the first verb in the sentence is in the past tense, all following verbs will have to be in the past tense as well.
So here, the first verb is <em>knew, </em>which is the past simple tense of the verb <em>to know, </em>which means that the following verb <em>to be </em>also has to be given in the past. The past simple form of the verb <em>to be </em>for plural is WERE.
A. Carbon dioxide is used to produce oxygen
