ike to invite you to a partytomorrow evening.– Thank you, but ______ I’ll be free I’muncertain.

The hotel was nice; the weather was warm; the beaches were beautiful ________ I’d say it was a great vacation

With time changing so fast, to keep _____ with time, anyone should be a lifelong learner, or he will fall behind within years.

______do you learn English so well_______chatting with my pen pal in America online.

下列句子中，没有语病的一项是(　　)