How much did the author know about the nuclear fission?
A.He was familiar with it.
B.He knew it profoundly.
C.He had never heard of it.
D.He knew little about it.
正确答案:He knew little about it.
How much did the author know about the nuclear fission?
A.He was familiar with it.
B.He knew it profoundly.
C.He had never heard of it.
D.He knew little about it.
正确答案:He knew little about it.