Questions 46~47 are based on the following reading.        The solar wind is a stream of energized, charged particles, primarilyelectrons and protons, flowing out from the Sun. When racing normally along atabout 450 km/s, it is usually harmless because of its low density, but when asudden burst occurs and emits large amounts of very fast charged particles, it cangust at up to 1,700 km/s or more, which can damage power systems, GPSnavigation, air travel, financial services and emergency radio communications.        People of the 21st century rely on high-tech systems for the basics of dailylife. A major solar storm could cause tremendous economic damages. Forexample, there are over 936 operating satellites in space, worth an estimated$200 billion to replace. The Sun is about to get a lot more active, following an11--year cycle. We cannot prevent solar storms, but we can monitor and givewarnings when stormy weather is approaching. Hopefully, appropriate actionssuch as putting satellites in 'safe mode' and disconnecting transformers to protectelectronics from electrical surges can be taken to limit the damages.
【題組】46. When a solar storm is coming, why do we need to disconnect transformers?
(A) to make routine maintenances
(C)to avoid electrical surges
(B) to repair damaged transformers
(D)so as to not to be blown away by