I feel it hard to keep up with my classmates in study and sometimes I lose heart. But whenever I want to ________ , my teacher always encourages me to work harder.

A．go on

B．run away

C．give up

D．look out

疟疾病原学诊断常用的方法为

A．浓集法

B．体外培养法

C．骨髓穿刺

D．厚、薄血涂片

E．动物接种法