She devoted herself _____ to her research and it earned her a good reputation (名声) in her field [ ]

won’t believe it, Sam. I was chosen as anexchange student to China.— Congratulations! _______

It suddenlytome that this was something that I should never do, so I turned down her request.

His answer was _______, so no one could make out whathe meant.

I often make mistakes ___________ grammar..