______Jim ______his cousin has been to America，but ________of them know the country well..

下列句子中，没有语病句意明确的一句是（ ）

Since entry into high school the students have been ________ staying up late in the evening and getting up early in the morning.

I have got used to staying up late at night I’m really tired and want to go to sleep early[ ]

Ballet is highly technical and itprofessional dancers years to train