tests by here4u with the online test builder (627 tests)

601. Too (much/many) or Enough (3692 candidates)
602. Verbs of involuntary perceptions ... (2278 candidates)
603. Infinitive, continued ! (1968 candidates)
604. Infinitive after verbs expressing will power ... (8488 candidates)
605. Not everyone has ... (2178 candidates)
606. What about suggesting ... (3996 candidates)
607. Difficulties of the Passive Form (16214 candidates)
608. 'Make someone do'/'Have something done': (a little further) (42696 candidates)
609. We'd still like to work on more tenses ...(2/2) (1739 candidates)
610. We want to work with tenses ...(1/2) (2396 candidates)
611. Two simultaneous actions in the past ... (12438 candidates)
612. Cause ? Aim? Not mixing the two concepts ... (22161 candidates)
613. Absence of obligation (25034 candidates)
614. To talk someone into / out of doing something ... (2434 candidates)
615. Difficulties in Reported Speech (15467 candidates)
616. Will and Would: a little further (7200 candidates)
617. Used to / to be used to (33915 candidates)
618. Present continuous (11913 candidates)
619. Past simple and continuous (8906 candidates)
620. Express future (11961 candidates)