impair, spoil
The holiday was marred by bad weather.
might could will
reverse
Instead of using the word challenging you can use the word gifted, special, special gifted.
One word for motivated is determined.
or
Will, when, why, it, can
It depends on the sentence. He, she, it, we, or they are possible, or you can just rearrange the sentence to say the same thing without using the word "you". Maybe you can rearrange it so it says "yourself" or something of that nature instead.
I belong in this family. -- belong (in). I am included in this family. -- included (in). I am a member of this family. - member (of) I am one of this family. -- one (of)
I have a stomach ache.
Myself
mixture