Student or Learner
The answer for the blanks is 1, but doesn't 3 also work?
*Michael always smiles at people. I want to know ________ he is always in a good mood.
*Have you lost your watch? I'll tell you ________ I find it.
1.if - if 2.that - if 3.how - when
Michael always smiles at people. I want to know if he is always in a good mood.
Whilst not entirely ungrammatical, it doesn't make any sense. If someone always smiled at people, I would want to know why he was always in such a good mood. At a push, I would wonder how [it was possible] that he was always in a good mood.
With the second sentence, "if" and "when" both fit.
Of the three, #3 is the least wrong answer but I think it's a bad test question.
Remember - if you don't use correct capitalisation, punctuation and spacing, anything you write will be incorrect.