The Internet has brought ____big changes in the way we work．

What people like to eat is subjective, but ______ the northerners like dumplings while the southerners are fond of rice. 

I soon found that the work I was doing had already been done by someone else. _______, I was wasting my time.

——Let’s go skating after school. ——_____ Call for me at any time.

She's aiming ________ a scholarship. That is why she has been focusing her mind ________ her work.