Try to match the words under the line; just drag the word that you think means "female cousin" into the rectangle, then do the same for the other words. If you chose the wrong word, the computer will not let you drop it into the box.
Note for parents. Please note that some words in Esperanto are more precise than in English, for example "cousin" might be female or male, so you need two English words to translate the Esperanto word "kuzino". This exercise also shows that learning Esperanto can help increase the child's English vocabulary. For example not every child will know what a female donkey is called.