Simple past crossword

What is the Simple Past? Complete the crossword, then click on "Check" to check your answer. If you are stuck, you can click on "Help" to get a free letter. Click on a number in the grid to see the clue or clues for that number.
           1     2      
       3    4               
            5           
6       7                  8   
   9           10             
   11                      
          12         13           
                  
14          15      16               
                  
   17           18              
                  
                 
                 

Across:

3. speak
5. take
7. send
10. ring
11. read
12. win
13. stand
14. sleep
16. spend
17. sell
18. wear

Down:

1. meet
2. think
4. put
6. understand
7. swim
8. say
9. write
10. run
13. sit
15. tell
16. see
17. sing