根据下面资料，回答31-35题
"Nature isn't classical, and if you want to make a simulation of nature you'd better make it quantum mechanical, and it's a wonderful problem because it doesn't look easy." With those words, in 1981, Richard Feynman introduced the idea that, by harnessing quantum mechanics, it might be possible to build a new kind of computer, capable of tackling problems that would cause an ordinary machine to choke. Over the past four decades quantum computers have slowly evolved from scrawls on theoreticians' blackboards to small machines in university laboratories to research projects run by some of the world's biggest companies.
Now one of those machines, built by researchers at Google, has at last shown what all the fuss is about. It appears to have performed, in just over three minutes, a task that the world's most powerful classical supercomputer would take around 10,000 years to complete. Google's machine is a special-purpose device that was designed to solve a contrived problem with few practical uses. But this display of so-called "quantum supremacy" is nonetheless a milestone.
What might quantum computing actually be used for? That question is obscured by the piles of money and hyperbole that surround it. Along with 5G and AI, it is one of the technologies that presidents, of both countries and companies, love to cite. There is excited talk of a race, and of the riches and power that await the first to seize the "Holy Grail of computing".
Despite the breathlessness, quantum computers are not magical. A rich body of theoretical work proves that they will be potent, but limited. For all the talk of supremacy, quantum computers are not superior in every regard to their classical cousins. Indeed for many tasks they will offer little improvement. Yet for some problems—but only some—clever programmers or mathematicians can create algorithms that exploit the machines' quantum capabilities. In those special cases, quantum computers offer huge gains, crunching tasks that would otherwise take years or millennia down to minutes or seconds.
Several of these algorithms have been developed. They offer a glimpse of where quantum computers might excel. In encryption, for example, a quantum machine could quickly untangle the complex maths that underlies much of the scrambling that protects information online. Tech firms and governments are investigating new foundations for encryption that are not known to be susceptible to quantum computers. But deploying them will be the work of decades.
However, Google's accomplishment strongly suggests the promise of quantum technology can be realized in practice as well as theory. And it will draw even more money and attention to a red-hot field. A great deal of engineering work remains before quantum computers can be used for real-world tasks. But that day has suddenly got closer.
By saying "you'd better make it quantum mechanical" (Para. 1), Feynman means that________

A quantum technology had already under his control at that time

B some mechanics are needed to build a quantum computer

C the quantum theory was first proposed by him as a theoretician

D conventional computers have a disadvantage in modeling nature