下列细胞中的染色体不成对的是[ ]

A．成熟的卵细胞

B．神经细胞

C．受精卵

D．口腔上皮细胞

As it turned out to be the most important meeting in the year, you ____ so casually.

A．Shouldn’t dress up

B．shouldn’t have dressed up

C．needn't have dressed up

D．couldn’t dress up