https://www.sightreadingfactory.com/
1.First click on Try it for free
2. Click on Strings
3. Click on your instrument
          violin, viola, cello(bass clef), double bass
4. click on 1
5. click on 2/4, 3/4 or 4/4
6. Click D major
7. You may choose free play or challenge
  Challenge: At the bottom you can change the tempo(how fast or slow you are going)
                         I recommend keeping the countdown at 30s so that you can look it over before you play
Then press start at the top

http://interactivesites.weebly.com/music.html
https://www.musictheory.net/
https://www.nyphilkids.org/games/main.phtml