题目内容：

    The 3D-printing industry is accelerating its efforts to help fight the new coronavirus and the disease it causes, COVID-19.

On Tuesday, HP announced it’s working with those who bought its 3D printers to make medical face shields, hands-free door openers and an adjuster for face masks for medical staff who often must wear them for hours. It’s also testing “hospital-grade” face masks meeting the higher-end FFP3 (过滤式面罩) standard and parts for simple emergency ventilators (呼吸机) and it’s looking into nasal swabs to test for COVID-19 infection. HP also is offering free downloads of its 3D-printed medical equipment designs.

Carbon, whose 3D printers are used to make everything from bicycle seats to teeth straighteners, said it plans to send face shield designs to its network of customers who’ve bought its 3D printers. Carbon co-founder and Executive Chairman Joseph DeSimone said on Monday the company expects to send the designs by early Tuesday.

3D-printcr makers typically sell their products to others that actually do the 3D printing. One such customer, Ford, said Tuesday that it’s made 1,000 face shields and shipped them to Michigan hospitals, with plans to make 100,000 face shields a week. It is also working with 3M and General Electric on respirator masks and ventilator designs.

The effort is one of several to apply 3D-printing technology to the fight against coronavirus. 3D printing isn’t as fast at churning out products as conventional mass production methods. But 3D printers are flexible and able to make many different parts anywhere there’s a printer and raw materials like the plastic resins Carbon printers use.

Some 3D-printing efforts have focused on ventilators, which expected to be in short supply with a surge of COVID-19 patients suffering from respiratory (呼吸器官) problems. Also in short supply arc N95 masks that can be useful in reducing the likelihood a wearer will spread COVID-19 to others.

Carbon’s DeSimone is cautious about the enthusiasm, though, saying that regulatory approval is important and that 3D-printcr enthusiasts shouldn’t be making components not intended for close human contact that might release unhealthy gases.

1.What is the passage mainly about?

A.An introduction about 3D-printing.

B.The 3D-printing industry’s efforts to help fight COVID-19.

C.The products that 3D-printing makers sell.

D.How 3D-printing makers produce medical equipment.

2.HP announced to help its customers to make the following products except for_____________.

A.medical face shields B.hands-free door openers

C.an adjuster for face masks D.emergency ventilators

3.Which of the following is true according to the passage?

A.Carbon’s company will finish its design after Tuesday.

B.Ford has made 1,000 face shields end plans to make 10,000 more in a week.

C.3D printers arc more flexible than traditional mass production methods.

D.Most 3D-printings focus on making ventilators and N95 because of their short supply.

4.What can be inferred from the last paragraph?

A.3D-printing may release unhealthy gases.

B.DeSimone is cautious about 3D-printing.

C.Carbon’s company didn’t gain regulatory approval of making medical equipment.

D.3D printers aren’t enthusiastic about making components designed for close human contact.