结肠癌TNM分期，Tis表示（）
A.原位癌
B.原发肿瘤未能检得
C.肿瘤侵及黏膜下
D.肿瘤侵及黏膜肌层
E.无原发肿瘤
参考答案：A
Dina, ______ for months to find a job as a waitress, finally took a position at a local advertising agency.[ ]
A. struggling
B struggled
C. having struggled
D. to struggle
肉苁蓉不但可以补肾助阳，还可以（）
A.益精活血
B.固精缩尿
C.润肠通便
D.温脾开胃
