题目内容：

    Humans make mistakes. Even surgeons with years of experience are not infallible. But what if these doctors could pool their knowledge and experience together and create a surgical standard of care, to be carried out by machines?

That's the idea behind surgical robots, which may soon perform most surgeries, from sewing up tiny wounds to performing heart procedures. Many of these operations are, in fact, already completed with the assistance of robots. But a recent test suggests that robots in the operating room may soon go a step further, performing on soft tissue completely on their own, from start to finish.

The Smart Tissue Autonomous Robot（STAR）, successfully completed surgeries on pigs. "We're the first group to develop autonomous robotic surgery with soft-tissue surgery, and when compared to standard operation, it's better, "says Peter Kim, professor of surgery. "The idea is not to replace surgeons；it will make the surgeons better and make the procedures safer. "

A recent Mayo Clinic study found that major surgical errors-including operating on the wrong site or side of the body, or even leaving tools or objects inside the patient-occur every one out of 22, 000 procedures. That's rare, but robots like STAR would aim to lower the number even further.

In the da Vinci surgical system, surgeons place their arms inside instruments and use their hands to control the movement of robotic tools on the operating table from afar. The robot's every major move is controlled by surgeons, and thus its results may vary based on the surgeon's training or experience.

STAR, on the other hand, is entirely autonomous. It's not only able to work on its own and perform surgeries with a more flexible "hand", but it's able to react to the unexpected incidents. Cutting into hard tissue like bones is one thing, but operating on moving soft tissue is far more complex. STAR reacts to a changing environment, similar to how self-driving cars are programmed to not only drive on the highway, but also react to another driver making a mistake and getting in your way.

1.The underlined word "infallible" in Paragraph 1probably means ______ .

A. quite smart    B. really creative

C. rather responsible    D. always right

2.We can learn from the passage that STAR ______ .

A. can perform the operation on its own

B. has been widely used in the operating room

C. can make surgeries much faster

D. will take the place of surgeons

3.In the da Vinci surgical system,  ______ .

A. robots are trained from afar    B. robots always make mistakes

C. surgery results depend on surgeons    D. surgeons have trouble controlling robots

4.In the last paragraph, the author mentions self-driving cars in order to show ______ .

A. how smart an autonomous robot can be

B. how difficult self-driving on the highway is

C. how bad getting in another driver's way might be

D. how dangerous operating on people is.