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问题 填空题
有代数式：（1）0；（2）-x；（3）
3
x2y3
2
；（4）
ab
π+2
；（5）
4b2c7
3a
；（6）
m+n
4
；（7）(
π
-1）R2，其中单项式有______（填序号）．
答案

（1）、（2）是单独一个数或字母，（3）、（7）是表示数与字母乘积，（4）π+2是数字，属于单项式；（6）m+n表示字母的和，是多项式；故单项式有（1）、（2）、（3）、（4）、（7）．

单项选择题

Questions from 36 to 40 are based on the following passage: A garment label is more than just a piece of fabric. It is something that draws the attention of customers to the garment. In today’s times, labels actually help in selling a garment. Customers decide whether to buy a piece of apparel or not on the basis of its label. Labels communicate to the customer what types of materials have been used in making the garment. Different manufacturers use their own special type of labels to create their own distinct identity. A label might be custom-made by a manufacturer to make it unique. Beautiful, customized labels add to the beauty and style of the garment. Each brand produced by the manufacturer is usually distinguishable on the basis of a special symbol, color or word. This is reflected through the label. Garment labels can be made using several fabrics, in different types of finishes and can be attached to the garment in different styles. The fabrics that are commonly used in the preparation of labels are satin, damask, semi-damask and taffeta. In some cases, cotton, canvas and felt are also used in making labels. Satin is the most used fabric in preparing labels. Leather labels are generally used in case of jeans and pants. PVC labels are used in pants and bags. Satin is soft on the skin and looks very pretty initially. However, it is not one of the best fabrics to be used in labels because it is very thin and can snag easily. Labels made using taffeta are stiffer than those of satin and do not snag as easily. However, taffeta labels can irritate the skin of the customers. Damask and semi-damask are ideal fabrics for making labels. Damask labels are soft even after finishing and do not cause any irritation to the customer. Semi-damask is similar to damask in feel, but it costs lesser than damask.

The most used fabric adopted in the labels is（）

A．felt

B．semi-damask

C．satin

D．leather
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单项选择题

下列氨基酸中能转化生成儿茶酚胺的是

A．天冬氨酸

B．色氨酸

C．酪氨酸

D．丙氨酸

E．蛋氨酸
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