句型转换.

1. He can speak a little Japanese. (改为一般疑问句)

    _____ he _____ a little Japanese?

2. Jack can do Chinese Kung Fu. (改为否定句)

    Jack _____ do Chinese Kung Fu.

3. Lucy and Sarah can sing and dance. (对划线部分提问)

    ______ can Lucy and Sarah _____?

视网膜的结构按主要细胞层次可简化为四层，由外到内依次为色素细胞层、（）、双极细胞层和神经节细胞层。