tests by nicks0206 with the online test builder (197 tests)
Ranked by: number of candidates
1. Pretérito indefinido: irregular (346932 candidates)
2. Verbos con diptongación (176330 candidates)
3. Soler + infinitive (156715 candidates)
4. Gustar, doler, encantar ... (156110 candidates)
5. El pretérito perfecto compuesto (136304 candidates)
6. Comparison : tan..como, tanto ..como, tanto/a/os/as..como (102759 candidates)
7. Imperfect (102579 candidates)
8. Adjectives agreement (100000 candidates)
9. Gerund (91579 candidates)
10. Present (80496 candidates)
11. Present (63675 candidates)
12. Animals (60176 candidates)
13. Conditional - SI + sequence of tenses (59056 candidates)
14. Pretérito Indefinido. Verbs in -ZAR, -CAR, -GAR (57154 candidates)
15. Colours (53649 candidates)
16. Do some shopping (49862 candidates)
17. Pretérito indefinido (46393 candidates)
18. VERBOS DE CAMBIO (45474 candidates)
19. What the weather like? (44971 candidates)
20. Pero .?.../...sino...? (43121 candidates)