1. Why is the Tom taller than Sam?

(Can we use 'the' before 'Tom' as in the example sentence?)

2. You feel like a magician.
3. You look like a fool.
4. That sounds like a great idea.
5. The melon smells like a bad fish.
6. The meal tastes like rice soup.

(Are the sentences all correct from #2 and #6?)

2 answers

no, I don't think so because the sentence doesn't sound good with it. You can just leave "the" out and the sentence will sound fine.
I agree with Kim on 1.

2 is not correct, since you really don't know how the other person feels or what feelings are connected to being a magician.

Although 3 is grammatically correct, it is not good to give an evaluative statement without indicating what leads to this conclusion. If the person does not want to "look like a fool," what can that person do differently? It is much better to describe undesirable behavior than to label people. Then there is a greater chance of getting the behavior to change. For example, "Putting lipstick beyond the boundaries of your real lips looks foolish." Here you are describing the behavior and labeling the behavior as foolish rather than the person. This is why I like 4 more than 3.

See http://www.members.cox.net/dagershaw/lol/LookingGlass.html

I hope this will help you learn more than just grammar. Thanks for asking.