[单项选择]

An Early Form of Jazz Music

Music comes in many forms; most countries have a style of their own. At the turn of the last century, (51) jazz was bona, America had no prominent (52) of its own. No one knows exactly when was invented or by whom. But it began to be (53) in the early 1890s. Jazz is America’s contribution to (54) music. In contrast to classical music, which (55) formal European traditions, jazz is spontaneous and free in form. It bubbles with energy, (56) the moods, interests, and emotions of the people. In the 1920s’ jazz (57) like America. And so it does today. The (58) of the music are as interesting as the music itself. American Negroes, or blacks, as they are called today, were the jazz pioneers. They were brought to the Southern states (59) slaves. They were sold to plantation owners and forced to work long hours. When a Negro died, his frien
A. while
B. when
C. since
D. as

[单项选择]
Music comes in many forms; most countries have a style of their own. At the turn of the last century, (51) jazz was bona, America had no prominent (52) of its own. No one knows exactly when was invented or by whom. But it began to be (53) in the early 1890s. Jazz is America’s contribution to (54) music. In contrast to classical music, which (55) formal European traditions, jazz is spontaneous and free in form. It bubbles with energy, (56) the moods, interests, and emotions of the people. In the 1920s’ jazz (57) like America. And so it does today. The (58) of the music are as interesting as the music itself. American Negroes, or blacks, as they are called today, were the jazz pioneers. They were brought to the Southern states (59) slaves. They were sold to plantation owners and forced to work long hours. When a Negro died, his frien
A. music
B. songs
C. melodies
D. tunes

[单项选择]

Medicine comes in many forms. In its liquid form, medicine affects the body very quickly. But the effects of liquid medicine arch’ t usually long-lasting. This is why pills and capsules (胶囊) are also used.
The pills and capsules being sold today arch’ t perfect, either. Pills dissolve in the stomach. The medicine in the pills is released when the pills dissolve. But often, the pills dissolve too quickly.
Scientists have been trying to develop a pill that can release medicine slowly over a long period of time. They have applied their knowledge of plants to produce the "osmotic (渗透的) pump pill".
The cell walls of plants are made of cellulose (纤维素). Cellulose is a very porous substance. Their holes are big enough to allow water through the cell walls. As water enters a cell, pressure builds up in the cell. The pressure pumps other substances out of the cell. These substances leave the cell through the cellulose wall. This slow, steady pr
A. it releases medicine slowly over a long period of time
B. it helps to build pressure in the body
C. the medicine in the pill can affect the body quickly
D. the coating doesn’t dissolve in the stomach