A:Until
B:Unle
C:Since
D:While
下列同学的话语中,体现了对父母的理解是( )
My friends thought they had made things very smooth for me, but I felt there was still much to ________ with.
下列有关免疫调节的说法,正确的共有( )个
①一个浆细胞(效应B淋巴细胞)只能产生一种抗体;②一个吞噬细胞可吞噬多种抗原;
③机体自身组织和细胞不可能成为抗原; ④一个记忆细胞可识别多种抗原;
⑤特异性免疫是非特异性免疫的基础; ⑥免疫功能过低会导致风湿性心脏病.
下列属于青藏地区自然景观的是( )