Hair loss is often be unwillingly accepted as a natural part of life.After all,most people,women included,will lose some or all of their hair as they get older.But when hair loss happens suddenly handfuls —it can be truly distressing.It can also be a signal of a health issue that needs to be addressed as soon as possible.
To understand why unexpected hair loss happens,it's useful to know the growth cycle of healthy hair.Usually,most of your hair is in a growing phase,during which strands lengthen by about 1.25 centimetres a month.This part of the cycle carries on for between two and eight years.After that,there's a middle phase,lasting about three weeks,during which the hair isn't getting longer but also isn't falling out.Finally,strands enter a resting phase,where the hair is loosened but sits in its follicle （毛囊）.Then,when the follicle begins to grow a new hair,the old one drops out.
Due to this cyclical process,we all lose up to 100 strands of hair each day. " At any one time,about ten per cent of our hair is in the falling out phase," explains Jennifer Jones,a dermatologist from London,UK，and an advisor to the British Association of Dermatologists.When that balance is disrupted，a person can have too much hair in the resting phase—and a few months later,he or she might find that a large amount comes out all at once.
Stress from sadness,divorce,or even moving house can cause hair loss.Another common cause is prescription drugs.In some cases,hair loss is subtle；other times,sufferers lose all their hair- including their body hair,eyebrows and eyelashes. "If you notice hair loss,you should discuss it with your doctor," says Jones. " We can often switch your medications." Treatment depends on the underlying cause.To discover that,a doctor might order blood tests,perform a small skin biopsy or examine the hairs under a microscope.If the loss is stress or drugs-related,it is usually temporary,and resolves within a few months without any intervention.



In which phase of its growth cycle will the hair get loosened？ ______

A. The growing phase.
B. The middle phase.
C. The resting phase.
D. The sitting phase.

What is the meaning of the underlined word " disrupted" in paragraph 3？ ______

A. Kept.
B. Broken.
C. Regained.
D. Developed.

What kind of life events is unlikely to cause hair loss？ ______

A. Getting a pet to keep you company.
B. Moving to a newly decorated house.
C. Getting divorced after years' suffering.
D. Taking drugs without your doctors' prescription.

Why will the doctor perform blood tests when you go to him for advice？ ______

A. To strengthen your hair quality.
B. To evaluate the conditions of your hair.
C. To perform a most suitable operation.
D. To work out the root cause effectively.