tests by bikette329 with the online test builder
(9 tests)
Ranked by: number of candidates
1. There is / there are (128728 candidates) 
2. Adverbs (27342 candidates)
3. Comparison (16174 candidates)
4. Past simple (11048 candidates)
5. Both and whereas (9469 candidates)
6. Present simple (4132 candidates)
7. A well-known legend (Arthur) (3736 candidates)
8. Past simple (1488 candidates)
(9 tests) Ranked by: number of candidates
1.
There is / there are (128728 candidates) 2.
Adverbs (27342 candidates) 3.
Comparison (16174 candidates) 4.
Past simple (11048 candidates) 5.
Both and whereas (9469 candidates) 6.
Present simple (4132 candidates) 7.
A well-known legend (Arthur) (3736 candidates) 8.
Past simple (1488 candidates) 