题干
He says he the Great Wall twice.
A：has been in
B：has been to
C：has gone to
D：has been for
答案(点此获取答案解析）
B
He says he the Great Wall twice.
A：has been in
B：has been to
C：has gone to
D：has been for
LiFePO4，电解质为导电固体。下列有关LiFePO4电池的说法正确的是
