更多"A. Leaves that have an offensive ta"的相关试题:
[单项选择]The leaves have been swept into huge heaps.
A. loads
B. layers
C. pyramids
D. piles
[单项选择] We all have offensive breath at one time or another. In most cases, offensive breath emanates from bacteria in the mouth, although there are other, more surprising causes.
Until a few years ago, the most doctors could do was to counsel patients with bad breath about oral cleanliness. Now they are finding new ways to treat the usually curable condition.
Bad breath can happen whenever the normal flow of saliva slows. Our mouths are full of bacteria feeding on protein in bits of food and shed tissue. The bacteria emit evil-smelling gases, the worst of which is hydrogen sulfide.
Mouth bacteria thrive in airless conditions. Oxygen-rich saliva keeps their numbers down. When we sleep, for example, the saliva stream slows, and sulfide-producing bacteria gain the upper hand, producing classic " morning breath".
Alcohol, hunger, too much talking , breathing through the mouth during exercise — anything that dries the mouth produces bad breath. So can stress, though it’’s n
A. they can’’t mask the bad odor long enough
B. they can’’t get to all the offending bacteria
C. their strong smell mixes with bad breath and makes it worse
D. they can’’t cover the thick layers of mucus
