To his surprise, the lifestyle he was used to ______ greatly in the past few years.
The approach _________ the problem is contrary ________ our expectations.
She is always thinking more of herself, seldom, ________, offering to help others.
---How often do you drop your e-pal a line?---_______, but usually once a week.
Our skin, if ______ to sunlight for a long time, can become darker.
_______ he met with the difficulty did he realize the importance of our help.