and reducing transportation and storage requirements．

Nutrition

Future 3D food printers could make processed food healthier．Hod Lipson, a professor at Columbia University, said, "Food printing could allow consumers to print food with customized nutritional content, like vitamins．So instead of eating a piece of yesterday's bread from the supermarket, you'd eat something baked just for you on demand．"

Challenges

Despite recent advancements in 3D food printing, the industry has many challenges to overcome．Currently, most ingredients must be changed to a paste(糊状物) before a printer can use them, and the printing process is quite time-consuming, because ingredients interact with each other in very complex ways．On top of that, most of the 3D food printers now are restricted to dry ingredients, because meat and milk products may easily go bad．Some experts are skeptical about 3D food printers, believing they are better suited for fast food restaurants than homes and high-end restaurants．

28．What benefit does 3D printing bring to food production?

A．It helps cooks to create new dishes．

B．It saves time and effort in cooking．

C．It improves the cooking conditions．

D．It contributes to restaurant decorations．

29．What can we learn about 3D food printing from Paragraphs 3?

A．It solves food shortages easily．

B．It quickens the transportation of food．

C．It needs no space for the storage of food．

D．It uses renewable materials as sources of food．

30．According to Paragraph 4, 3D-printed food ________．

A．is more available to consumers

B．can meet individual nutritional needs

C．is more tasty than food in supermarkets

D．can keep all the nutrition in raw materials

31．What is the main factor that prevents 3D food printing from spreading widely?

A．The printing process is complicated．

B．3D food printers are too expensive．

C．Food materials have to be dry．

D．Some experts doubt 3D food printing．

32．What could be the best title of the passage?

A．3D Food Printing：Delicious New Technology

B．A New Way to Improve 3D Food Printing

C．The Challenges for 3D Food Production

D．3D Food Printing：From Farm to Table

　　　　　　　　　　　　　　　　　　　　　D

In the 1760s, Mathurin Roze opened a series of shops that boasted（享有）a special