tests by nicks0206 with the online test builder (197 tests)
Ranked by: number of candidates
1. Pretérito indefinido: irregular (343500 candidates)
2. Verbos con diptongación (174904 candidates)
3. Soler + infinitive (155925 candidates)
4. Gustar, doler, encantar ... (155302 candidates)
5. El pretérito perfecto compuesto (135871 candidates)
6. Comparison : tan..como, tanto ..como, tanto/a/os/as..como (102441 candidates)
7. Imperfect (101951 candidates)
8. Adjectives agreement (99237 candidates)
9. Gerund (90981 candidates)
10. Present (80015 candidates)
11. Present (63363 candidates)
12. Animals (59839 candidates)
13. Conditional - SI + sequence of tenses (58830 candidates)
14. Pretérito Indefinido. Verbs in -ZAR, -CAR, -GAR (56614 candidates)
15. Colours (53397 candidates)
16. Do some shopping (49713 candidates)
17. Pretérito indefinido (46198 candidates)
18. VERBOS DE CAMBIO (45176 candidates)
19. What the weather like? (44659 candidates)
20. Pero .?.../...sino...? (42795 candidates)