—Sorry, Sir. I can't remember all the new words we learn every day.
—________. Practice more.
A：I'm afraid not
B：It's hard to say
C：You are not alone
D：All right
黄瓜果肉细胞和人的口腔上皮细胞都有的结构是（ ）
①细胞壁
②细胞膜
③细胞质
④细胞核
⑤线粒体
⑥叶绿体
⑦液泡
寡人以五百里之地易安陵。（ ）
