N1 1 is flowing 2 complain 3 walk 4 borrow N2 1 began 2 had 3 took 4 worked N3 1 was eating 2 was hurrying 3 were preparing 4 was arguing N4 1 found 2 was reading 3 was playing 4 fell N5 1 has studied 2 has dropped 3 has rained 4 have had N6 1 bigger 2 most difficult 3 better (well)