A-A+
A．They have already existed.B．They will come i
问题详情
A．They have already existed.
B．They will come into being in the future.
C．They are only people"s unrealistic dreams.
D．They may be put into commercial use very soon.
参考答案
正确答案：B
解析：语意推断。原文“Just wait，they probably will”要表达的含义：纸质飞机会问世的。
