There are many parts to this process, the things that the user drags, the targets the user can drop on and the way the score is shown. Take care with the process as you work your way through it.
It is best to begin with the layout of the page. In this case I have a headline and the text and a button. I will add a drop down list in a moment. The idea is that the user selects missing words from a drop down list and then the computer checks that the answers are correct. You will notice that the size of teh text has been increased - this makes adding the list boxes easier.
Now add a list box over one of the words. As you can see, I have chose then word "word".
Now add the data to the listbox so that the user has a range of options.
Select three or four words to be replaced by list boxes. Note that I have named the listboxes for the missing word so that I know which box is which.
Now add some code to the listboxes so the user knows that their selection has been accepted. On the drop down list box select the action "On Select" from the bottom of the list of actions. Then select an action - I have chosen to change the background colour to pink to show that a value has been selected.
The code for the button involves the code detecting that the right value has been selected.
The essential code is
Listbox_word.selectedstring = "word"
the property selectedstring is the value of listbox that the user has selected.
The finished code for the button will have one if statement for every listbox.