You would need to post the article or biography that it is asking for (:
NaF is not covalent, but ionic, as Na and F are on opposite sides of the periodic table.
Hi, you've asked an incomplete/unclear question. The full question read;
Which of the phrases below is <u>not</u> in the future perfect continuous?
a) You will have been waiting here for three hours by 8 o'clock.
b) You will be waiting for her when her plane arrives tonight.
c) By the end of next month I will have been living here for ten years.
d) When I finish this course, I will have been learning Italian for ten years.
e) Next month I will have been working here for two years.
Answer:
<u>b) You will be waiting for her when her plane arrives tonight.</u>
Explanation:
We make this conclusion because the phrase <em>"will have been" </em> (which is the future perfect of the verb "to be") is often added to the subject of a sentence to make it future perfect continuous.
However, after careful check of all the sentences, we notice all of them except option b used the future perfect continuous phrase, <em>"will have been." </em>
