B. By recording all the sounds.

C. By analyzing the sound of their cries.

D. By asking parents about specific messages.

9. What was the app designed for in the beginning?

A. All new parents. B. Deaf parents.

C. Ariana Anderson. D. Crying babies.

10. What is Ball's opinion about the app?

A. Parents should use the app wisely.

B. The app can create an accurate result.

C. Parents and babies are addicted to the app.

D. The app makes babies lose love and caring.

11. What is the text mainly about?

A. Parents should not rely too much on their smartphones.

B. A new app helps parents figure out why their babies are crying.

C. Parents can deal with babies' hunger with the help of a new app.

D. A new app called ChatterBaby can prevent babies from crying.

Harvard researchers have created a tough, low-cost, biodegradable(可生物降解的) material inspired by insects' hard outer shells. The material's inventors say it has a number of possible uses and some day could provide a more environmentally friendly alternative（可替代的） to plastic. The material, made from shrimp shells and proteins produced from silk, is called "shrilk". It is thin, clear, flexible（柔韧性的） and strong.

A major benefit of the material is its biodegradability. Plastic's toughness and flexibility represented a revolution in materials science during the 1950s and 1960s. Decades later, however, plastic's durability(耐用性) is raising questions about how appropriate it is for one-time products such as plastic bags, or short-lived consumer goods, used in the home for a few years and then cast into a landfill where they will degrade for centuries. What is the point of making something that lasts 1,000 years?

Shrilk not only will degrade in a landfill, but its basic components are used as fertilizer, and so will enrich the soil. Shrilk has great potential, the inventors said. Materials from which it is made are plentiful in nature, found in everything ranging from shrimp shells, insect bodies to living plants. That makes shrilk low cost, and its mass production possible if it should be used for products demanding a lot of material.

Work on shrilk is continuing in the lab. The inventors said the material becomes flexible when wet, so they're exploring ways to use it in wet environments. They're also developing simpler production processes, which could be used for non-medical products, like for computer cases and other products inside the home. They're even exploring combining it with other materials, like carbon fibers, to give it new properties.

12. Paragraph 1 of the passage is mainly about shrink's .