Scientists from Cambridge University have made a special machine. It uses sunshine and car battery acid (电池用酸) to break down plastic trash.

People make too much plastic every year, and most plastic is difficult to recycle (回收利用). Old recycling ways are slow and often fail to work well.

Inside this new machine, a special “super helper” (called a catalyst) uses sunlight to change plastic into clean gas and other useful things. The machine can run for a long time without breaking down, and it’s cheap to use. Even better, the things it makes can be sold to make money! 

1.1. The machine helps to deal with (处理) ________.

A water

B air

C trash

D food

解析：选C。C 细节理解题。根据短文第一段第二句“It uses sunshine and car battery acid (电池用酸) to break down plastic trash.”可知，这台机器是用来分解塑料垃圾的。题目问机器处理的对象，即“trash”（垃圾）。A项（水）、B项（空气）、D项（食物）在描述机器功能的句子中均未涉及，且与“plastic trash”无关联。故选C。

2.2. Old recycling ways are ________.

A bad

B cool

C clean

D fast

解析：选A。A 细节理解题。根据短文第二段的“Old recycling ways are slow and often fail to work well.”可知，旧的回收方式速度慢，而且常常效果不佳，即旧的回收方式不好。故选A。

3.3. The machine turns plastic into ________.

A clean gas

B dirty water

C new plastic

D used batteries

解析：选A。A 细节理解题。根据第三段的“to change plastic into clean gas and other useful things”可知，机器将塑料转化为了清洁气体。题目询问转化的产物，即“clean gas”。B项“dirty water”（脏水）文中未提；C项“new plastic”（新塑料）与机器分解塑料的功能相反；D项“used batteries”（废旧电池）是机器使用的原料之一，而非产物。故选A。

4.4. The machine is ________.

A heavy and loud

B expensive and big

C old and slow

D cheap and useful

解析：选D。D 细节理解题。根据短文第三段最后两句“The machine can run for a long time without breaking down, and it’s cheap to use. Even better, the things it makes can be sold to make money!”可知，这台新机器不仅成本不高（便宜），而且效果好、能赚钱（有用）。题目询问机器的特点，即“cheap and useful”。A项“沉重且吵闹”文中未涉及机器的重量和噪音描述；B项“昂贵且大”价格与原文完全相反，且未提及体积；C项“老旧且慢”文中未提及机器运行速度。故选D。