My Primary 6 brother's homework

I was asked to look through his homework to check for him, and i came upon these questions..

16. The ____ Boy always does things without any careful consideration.

(1) optimistic
(2) impulsive
(3) considerate
(4) aggressive

Well, this is pretty straightforward, and didn't scare me so much.. its the others that made me wow.

17. Mr Tan was very nervous when he was asked to do a ______ presentation.
(1) incredible
(2) immediate
(3) impromptu
(4) impossible

... I'm sure if you asked this question to my sec 5N(a) classmates 4 years ago... or even now. They would have no idea what impromptu is ... or mean.

I kid you not. Do You know what's impromptu? Sheesh.. and p6 students have to do this ar..

There are a few more questions... hmm, try this.

That old man who lives alone is very peculiar. He seldom comes out of his house and never has any visitors.
(1) Aloof
(2) funny
(3) strange
(4) unfriendly

.. i seriously can't confirm whether its (1) aloof, or not. man. how am i supposed to teach my brother?

I'll just do my best..~