The scientists ______ the mystery of the double helix, the scope for genetic engineering dramatically increased.
A．having solved
B．after being solved
C．solving
D．solved

未分类题Our difference, ______, is one of method, not one of principle.A．which I seeB．as I see itC．that I seeD．I see

未分类题The students were so fascinated by the______Yangtze River that they spent hours sitting on its bank and gazing at the passing boats and rafts.A．medianB．mightyC．measurableD．maximal