题目:
Sophisticated laser-guided land graders can now flatten uneven farmland almost perfectly so as not to waste rainwater in runoff down sloping fields.
选项:
A、so as not to waste rainwater
B、so that rainwater is not wasted
C、so that there is no wasted rainwater
D、and thereby not waste rainwater
E、and there is no rainwater wasted
答案:
B