The university started some new language programs to _____ the country’s Silk Road Economic Belt.

Jane can’t attend the meeting at 3 o’clock this afternoon because she ______ a class at that time.

I ______ have worried before I came to the new school, for my classmates here are very friendly to me.

Despite the previous rounds of talks, no agreement______ so far by the two sides.

Tom had to______ the invitation to the party last weekend because he was too busy.