SimilarityRank
be_tough 0.779 11759
it_be_a_tough 0.746 93393
a_tough 0.721 26323
a_difficult 0.698 12053
tough 0.683 4367
it_be_tough 0.612 29779
be_a_challenging 0.597 67849
be_very_hard 0.585 91214
be_the_most_difficult 0.581 91080
a_tricky 0.572 79167
be_quite_a 0.569 25697
hard 0.566 1452
be_an_interesting 0.558 29539
difficult 0.557 2515
be_very_difficult 0.554 37607
be_not_easy 0.551 17254
it_be_not_easy 0.547 29647
very_hard 0.537 41193
the_most_challenging 0.530 54484
the_most_difficult 0.515 35489
really_hard 0.513 64966
very_difficult 0.512 34974
rough 0.509 7325
it_be_a_long 0.507 52581
be_a_very_good 0.506 36953