【单选题】Singing Alarms Could Save the Blind If you cannot see, you may not be able to find your way out of a burning building - and that could be fatal. A company in Leeds could(51) all that with directional ...
【简答题】When we see well, we do not think about our eyes very often. It is only when we cannot see perfectly that we realize how important our eyes are. People who are near-sighted can only see things that ar...
【单选题】When we see well, we do not think about our eyes very often. It is only when we cannot see perfectly that we realize how important our eyes are. People who are near-sighted can only see things that ar...