The habit-forming process within our brains is a three-step loop （回路）． First， there is a cue， a trigger that tells your brain to go into automatic mode （模式） and which habit to use． Then there is the routine， which can be physical or mental or emotional， Finally， there is a reward， which helps your brain figure out if this particular loop is worth remembering for the future． Over time， this loop-cues， routine， reward becomes more and more automatic． The cue and reward become intertwined （交织） until a powerful sense of anticipation and a desire appears． Eventually， a habit is born．
Habits aren't destiny． Habits can be ignored， changed， or replaced． But the reason the discovery of the habit loop is so important is that it reveals a basic truth： When a habit appears， tile brain stops fully participating in decision making． It stops working so hard， or shifts focus to other tasks． So unless you deliberately fight a habit-unlesss you find new routines-the pattern will unfold automatically．
Habits never really disappear． They're encoded （嵌入） into the structures of our brain， and that's a huge advantage for us， because it would be awful if we had to relearn how to drive after every vacation． The problem is that your brain can't tell the difference between bad and good habits， and so if you have a bad one， it's always lurking （蛰伏） there， waiting for the right cues and rewards．
This explains why it's so hard to create exercise habits， for instance， or change what we eat． Once we develop a routine of sitting on the sofa， rather than runing， or snacking whenever we pass a doughnut box， those patterns always remain inside our heads． By the same rule， though， if we learn to create new neurological （神经系统的） routines that overpower those behaviors-if we take control of the habit loop-we can force those bad tendencies into the background． And once someone creates a new pattern， studies have demonstrated， going for a jog or ignoring the doughnuts becomes as automatic as any other habit．
Of course， those decisions are habitual， effortless． As long as your basal ganglia （基底核） is complete and the cues remain constant， the behaviors will occur unthinkingly． At the same time， however， the brain's dependence on automatic routines can be dangerous． Habits are often as much a curse as a benefit．



What can we learn about the habit loop from the first two paragraphs？ ______

A. It helps your brain understand what is worth remembering．
B. It is a three-step loop consisting of a cue， a routine and a reward．
C. It becomes automatic and develops a sense of anticipation and desire．
D. It reveals a basic truth that the pattern of a habit wilt unfold automatically．

The advantage of habits never really disappearing is that ______ ．

A. we can easily change what we eat
B. we develop a routine of sitting on the sofa
C. we don't necessarily learn a skill again
D. we can distinguish between bad and good habits

What can be inferred from the last sentence in Paragraph 4？ ______

A. Habits can be changed and replaced．
B. Habits can not be ignored or created．
C. Old patterns always exist in our brain．
D. New patterns seldom remain in our heads．

What does the passage mainly talk about？ ______

A. The discovery of the habit loop．
B. The automatic pattern of habits．
C. The research on the habit-forming process．
D. The brain's dependence on automatic routines．