单项选择题 ‍砌体材料中块体的表示符号为？‏ A、M B、MU C、Mb D、Mc E、Me

单项选择题 Which is true about Embryonic Stem Cells.  A、They no longer do mitosis, their cell type is set and can not change B、 They are limited to the type of cell they can become C、They can become any cell type in the body D、They are found in adults E、All of the above.

单项选择题 puts(str)函数是将str中存放的字符串输出到显示器，自动将字符串结束标志“\0”转换为回车换行符。 A、正确 B、错误