tests by bikette329 with the online test builder
(9 tests)
Ranked by: number of candidates
1. There is / there are (126002 candidates) 
2. Adverbs (26875 candidates)
3. Comparison (15965 candidates)
4. Past simple (10944 candidates)
5. Both and whereas (9411 candidates)
6. Present simple (4124 candidates)
7. A well-known legend (Arthur) (3725 candidates)
8. Past simple (1486 candidates)
(9 tests) Ranked by: number of candidates
1.
There is / there are (126002 candidates) 2.
Adverbs (26875 candidates) 3.
Comparison (15965 candidates) 4.
Past simple (10944 candidates) 5.
Both and whereas (9411 candidates) 6.
Present simple (4124 candidates) 7.
A well-known legend (Arthur) (3725 candidates) 8.
Past simple (1486 candidates) 