Is it possible to say :

1. What can I do to show you I am sorry for forgetting your birthday? Word-amends

How can I make amends your birthday? in bold is what I think must be the left sentences is shown in the exercise.

2. You are making this exercise more difficult and complicated than it actually is.

You are .................this exercise. - Word - weather - NO Idea!

3. I can't understand these instructions at all.Word - sense

I can't make sense these instructions.

4. I really can't decide where to go on holiday!WOrd - mind

I can't make up my mind where to go on holiday!

Thank you in advance
1. How can I make amends for forgetting your birthday?

2. I have no idea how you would use the word "weather" in this context. Are you sure that's the right word?

3. I can't make sense of these instructions.

4. correct.
From Wikipedia

The term Heavy Weather could refer to any of the following:

  • As a phrase, heavy weather is of nautical derivation and refers to something that is more difficult than it should be.

    Example: "Getting gas from Bangladesh would have been any easy proposition, but for our politicians' and bureaucrats' making heavy weather of it."
Students: Are you brave enough to let our tutors analyse your pronunciation?
yes - the word is weather!
 nona the brit's reply was promoted to an answer.
Students: We have free audio pronunciation exercises.
Yes, "to make heavy weather" of something.