问题：

[共享题干题]根据下面材料，回答题。     How to Lose Weight Properly     Researchers stress that we need diet and exercise to drop pounds. "The most ____51____ way to lose weight is with a combination," says Rena Wing, head of the National Weight Control Center.     ____52____ experts also admit that many ____53____ losers find it helps to ____54____ on one or the other. "A lot of people feel helpless at the thought of ____55____ everything--diet, lifestyle," says Bess Marcus,professor of human behavior at Brown University Medical School. "So ask yourself, ' ____56____ do I want to start? What am I willing to focus on?'"     The ____57____ depends on everything from what you hope to ____58____ to how our life is ____59 .____     If you are in a big hurry to drop pounds ____60____, dieting is the way to go. Decades of ____61____ have shown it's the surest and quickest method. If you are more ____62____ with how you look than with numbers on the scale, though, ____63____ may be the way go to. By increasing physical activity, you'll ____64____ fat and build muscle tissue.____65____ often end up losing both fat and muscle tissue.     Your best approach is one that suits your lifestyle. If you've tried and fail at one approach, consider the other. "A lot of people have so disappointed that they begin to think they'll never be able to lose weight," says Marcus. "That's when it's time to try something new. Even a small step forward can help people regain confidence and convince themselves they can make even bigger changes."
不定项选择题第1题__________
A.Activist
B.Practitioner
C.Dieter
D.Exerciser