阅读理解。

     My name is Charlie Street. I'm not twelve. I am eleven. I'm not in Grade Eight. I am in Grade Seven. I'm in Class Two. My teacher isn't Miss Black. My teacher is Mr Grey. My phone number is 6688469.

1. What is my last name?

    __________

2. How old am I?

    __________ 

3. What grade am I in?

    In Grade __________.

4. Who is my teacher?

    __________ __________.

5. What class am I in?

    In Class ________

单卵双胎若分裂发生在桑椹期(早期囊胚)

A．可以发育成包人性寄生胎或胎内胎

B．可以导致不同程度不同形式的联体儿

C．将形成两个独立的受精卵，两个羊膜囊，两个绒毛膜，可以独立着床，形成各自的胎盘

D．将各自形成独立的胚胎，形成双羊膜囊单绒毛膜共有一个胎盘

E．胚胎各自发育成两个胎儿，共用一个胎盘，共存于一个羊膜腔内