如图是体重常见的红外线感应水龙头，当手对着红外线感应窗时，水会自动流出．

（1）使用该水龙头时，感应窗发出的红外线照射到手上发生了　 　，感应窗内的红外线接收管接收到信号后控制出水．

（2）当手一直处在感应范围内时，该水龙头在连续出水4秒后却自动停水6秒，如此反复．某人用20秒洗手一次，则使用该水龙头比使用持续出水的普通水龙头能节水　 　毫升．（该水龙头的水流量均为30毫升/秒）

Although interior design has existed since the beginning of architecture, its development into a specialized field is really quite recent. Interior designers have become important partly because of the many functions that might be (51) in a single large building.

The importance of interior design becomes (52) when we realize how much time we (53) surrounded by four walls. Whenever we need to be indoors, we want our surroundings to be (54) attractive and comfortable as possible. We also expect (55) place to be appropriate to its use. You would be (56) if the inside of your bedroom were suddenly changed to look (57) the inside of a restaurant. And you wouldn’t feel (58) in a business office that has the appearance of a school.

It soon becomes clear that the interior designer’s most important basic (59) is the function of the particular (60) .

51().

A.consisted 

B.contained 

C.composed 

D.comprised