Yes, your sentence is correct assuming you are talking to someone in the present and asking about their current thoughts.

You might try verbix.com but I'm not sure if it's accuracy. Maybe a native speaker can verify its worth for both of us.

...beyond the art found in traditional museums... ...early examples. Miniature Japanese Shinto shrines on roadsides are others. Cathedrals with elaborate stone designs and colorful glass windows...

Drop like flies is an idiom that we use when a group rapidly collapses or dies. So the Truvia was causing the actual flies to die out quickly and in larger numbers. But, scientists don't know why. In English, we say that a clock makes a ticking noise as the hands go around. So what makes you tick is the thing that makes you happy or keeps you going. When we talk about your ticker, we are talking about your heart. Also, a reference to the steady beat of the second hand on a clock.

I think we would say that student is the teacher's helper. If it is another student but who isn't actually taking that course but comes to help, then we would say teacher's aide. Or TA. But we don't generally have a set person who does those jobs on a daily basis so far as I know.

It means to feel relaxed, not worried and comfortable in a situation.

It is usually used to make a request of someone without making it an actual question. I don't think it's a common construction though.