Здрасти, помогите пожалуйста с заданием :(Read the definitions of the following

Здравствуйте, помогите пожалуйста с заданием :(

Read the definitions of the following words and put the right word into the gaps.

merry - causing happiness; pleasant, delightful;
happy - delighted, pleased, or glad;
cheerful - full of cheer, in good spirits;
joyful - showing or expressing joy, in looks, actions, or speech.


1) They were so ________ to see us.
2) He heard a _______song and felt ______.
3) A ____ child мейд everyone.

И если не трудно, напишите, почему конкретно такие слова подобрали(