Whenever I go to Beijing, ____ is quite frequent, I will go to visit the Great Wall

So absorbed _______ in her work that she didn’t realize it was time that she picked up her daughter.

Is there ____ European wolf in _____ zoo

I can think of many cases students obviously know a lot of English words and expressions but couldn’t write a good essay．

It was dark, so we decided to ______ for the night at the farmhouse.