题目

图1为植食性昆虫迁入该生态系统后的种群数量增长速率变化曲线，图2为λ（λ是当年种群数量与前一年种群数量的比值）随时间的变化曲线。下列有关叙述，正确的是A. 图1中t1～t2与图2中a～b时期种群都是衰退型B. 图2中a、c时期种群的出生率均与死亡率相当C. 图1和图2中K值出现的时间分别是t2和dD. 图1和图2可分别表示种群的S型和J型增长过程2．I'm _________ to hear that Bob's asked Susan to marry him．They're both my good friends and I've always thought they were made for each other．I know they'll be very happy together．A．green with envyB．feeling blueC．tickled pinkD．white as a sheet