tests by nicks0206 with the online test builder (197 tests)
Ranked by: number of candidates
1. Pretérito indefinido: irregular (341582 candidates)
2. Verbos con diptongación (174333 candidates)
3. Soler + infinitive (155515 candidates)
4. Gustar, doler, encantar ... (154927 candidates)
5. El pretérito perfecto compuesto (135651 candidates)
6. Comparison : tan..como, tanto ..como, tanto/a/os/as..como (102276 candidates)
7. Imperfect (101692 candidates)
8. Adjectives agreement (99009 candidates)
9. Gerund (90761 candidates)
10. Present (79864 candidates)
11. Present (63160 candidates)
12. Animals (59731 candidates)
13. Conditional - SI + sequence of tenses (58717 candidates)
14. Pretérito Indefinido. Verbs in -ZAR, -CAR, -GAR (56359 candidates)
15. Colours (53323 candidates)
16. Do some shopping (49649 candidates)
17. Pretérito indefinido (46076 candidates)
18. VERBOS DE CAMBIO (45082 candidates)
19. What the weather like? (44587 candidates)
20. Pero .?.../...sino...? (42643 candidates)