Which two sentences correctly use a dash?
most of the working population today is troubled—by lack of sleep.
you need to sleep 6—8 hours daily to maintain a healthy body.
the secret to improving your productivity is simple—get a good night's rest.
i found something unexpected in my trash can—a litter of raccoons.

The last two are the correct answers

Explanation:

A dash is used to separate groups of words, while a hyphen is used to separate parts of words. That’s why the second answer is wrong.

I also got this right on my test so this answer is reliable

what is   the question

the present continuous is a verb tense which is mainly used to indicates that an action is in progress at the moment of speaking.  

it is formed using: person + verb to be (am/is/are) +verb + - ing form  

example: i am studying at this moment .

in addition, the present continuous is also used in order to express things that will or will not happen in the near future.

example: i am having dinner with some friends tonight.

the speaker sometimes   uses it   to express that an action is repeated and it causes irritation on the part of the speaker

example: my sister is constantly complaining about everything.