Ответ
11) have been standing,told
12)was,lost,felt
13)hasn't seen,started
14)have been sleeping
15)can not,is
16)have just seen,Have you seen,haven't,read
17)flying,is arriving,need to leave
18)sells
19)has been waiting,had been,had gone,came,could not
20)used to ski,broke,haven't ski