tests by nicks0206 with the online test builder (197 tests)
Ranked by: number of candidates
1. Pretérito indefinido: irregular (345894 candidates)
2. Verbos con diptongación (175941 candidates)
3. Soler + infinitive (156436 candidates)
4. Gustar, doler, encantar ... (155800 candidates)
5. El pretérito perfecto compuesto (136134 candidates)
6. Comparison : tan..como, tanto ..como, tanto/a/os/as..como (102622 candidates)
7. Imperfect (102192 candidates)
8. Adjectives agreement (99424 candidates)
9. Gerund (91401 candidates)
10. Present (80159 candidates)
11. Present (63453 candidates)
12. Animals (59958 candidates)
13. Conditional - SI + sequence of tenses (58971 candidates)
14. Pretérito Indefinido. Verbs in -ZAR, -CAR, -GAR (56903 candidates)
15. Colours (53501 candidates)
16. Do some shopping (49765 candidates)
17. Pretérito indefinido (46292 candidates)
18. VERBOS DE CAMBIO (45340 candidates)
19. What the weather like? (44846 candidates)
20. Pero .?.../...sino...? (42995 candidates)