[单项选择]（　） scientists develop new ways of feeding the human race, the crowded conditions on earth will make it necessary for us to look for open space somewhere else.
A. Until
B. Since
C. Once
D. Even if

Scientists Develop Ways of Detecting Heart Attack
German researchers have (1) a new generation of defibrillators and early warning software aimed at offering heart patients greater protection (2) sudden death from cardiac arrest.
In Germany alone around 100,000 people die annually as a result of cardiac arrest and many of these cases (3) by disruption to the heart’s rhythm. Those most at risk are Patients who have (4) suffered a heart attack and for years the use of defibrillators has proved useful in diagnosing (5) disruptions to heart rhythms and correcting them automatically by intervening within seconds. These devices (6) a range of functions such as that of pacemaker.
Heart specialists at Freiburg’s University Clinic have now achieved a breakthrough with all implanted defibrillator (7) of generating a six-channel electrocardiogram(ECG) within the body. This integrated system allows ea
A. of
B. with
C. for
D. in