题目

Knowing office rules — whether _______ or not—is critical, especially for young job seekers.    A. written B. writing    C. being written        D. having been written 答案：A在洋葱表皮细胞质壁分离现象中，与细胞壁分离的是（    ） A. 细胞质       B.  细胞核       C.  原生质        D.原生质层