tests by here4u with the online test builder (672 tests)

501. Expressing time: by... , by the time..., once... (5943 candidates)
502. Before - In front of - Opposite... (8569 candidates)
503. Vocabulary: Swimming, diving... (2711 candidates)
504. Who - What - Which (24333 candidates)
505. Infinitive implied by its particle. (3360 candidates)
506. Doing, Do, To do... (9358 candidates)
507. Choosing your past tense... (47823 candidates)
508. Tenses : satisfying the request... (2) (2121 candidates)
509. The use of tenses: a strange request...(1) (3617 candidates)
510. Either...or/ Neither...nor/ Not ... either. (13465 candidates)
511. There is / are, and other forms... (5064 candidates)
512. To be / to have: -ing forms... (4294 candidates)
513. Enough with the Present Perfect... (21797 candidates)
514. Whose and use (5452 candidates)
515. Else and compound words (3723 candidates)
516. What, which and all that (7011 candidates)
517. Possessive idioms (3110 candidates)
518. Possessive or genitive Case (27587 candidates)
519. Possessive adjectives and pronouns. (25722 candidates)
520. Adjectives: where to place them? (17668 candidates)