thank you

1 have,has,having,had,had
2 go,went,come
3 interesting,boring,interest
4 difficult,difficulty,more difficult,the most difficult
5 relaxed,relax
6 same,different
7 with,without
8 they,them,their,themselves
9 tomato,tomatoes
10 well,better,the best
11 question,problem
12 healthy,health,healthily,sick,healthier
13 really,real
14 big,small
15 woman,man,women
16 look,see
17 get,got,got
18 twelve,twelfth
19 buy,sell,bought,bought
20 happy,happily,happie