不定项选择题第1题第48题____________
A.A limited water suppl
B.So that it can be used again just as if it were fresh from a sprin
C.It is possible to purify large amounts of sea wate
D.But even if every large city purified and reused its wate
E.And we cannot even use all of tha
F.Experiments have already been done in this fiel
参考答案:F
不定项选择题第2题第49题____________
A.A limited water suppl
B.So that it can be used again just as if it were fresh from a sprin
C.It is possible to purify large amounts of sea wate
D.But even if every large city purified and reused its wate
E.And we cannot even use all of tha
F.Experiments have already been done in this fiel
参考答案:B
不定项选择题第3题第46题____________
A.A limited water suppl
B.So that it can be used again just as if it were fresh from a sprin
C.It is possible to purify large amounts of sea wate
D.But even if every large city purified and reused its wate
E.And we cannot even use all of tha
F.Experiments have already been done in this fiel
参考答案:E
不定项选择题第4题第47题____________
A.A limited water suppl
B.So that it can be used again just as if it were fresh from a sprin
C.It is possible to purify large amounts of sea wate
D.But even if every large city purified and reused its wate
E.And we cannot even use all of tha
F.Experiments have already been done in this fiel
参考答案:A
不定项选择题第5题第50题____________
A.A limited water suppl
B.So that it can be used again just as if it were fresh from a sprin
C.It is possible to purify large amounts of sea wate
D.But even if every large city purified and reused its wate
E.And we cannot even use all of tha
F.Experiments have already been done in this fiel
参考答案:D