The scientist knows nothing about the matter, because he is always ______ himself in scientific study.

How about your travel? — You can hardly imagine what difficulty we have had ______ the vast desert. [ ]

Robert had __________ talent for dancing and he was ________ great success at the age of 18.

Look，what a mess in the kitchen！—I ______cooking fish in a new way and I really have no time to tidy it up now.

He has limited himself ______ 2,200 calories per day to try to keep fit[ ]