过圆x2+y2+2x﹣4y=0的圆心,且与直线2x+3y=0垂直的直线方程为____
在一个生态系统中,不可缺少的成分是 ( )。①非生物的阳光、空气和水等 ②生产者 ③消费者 ④分解者
(____) 1. A. shine B. ship C. school D. shop
(____) 2. A. book B. cook C. food D. good
(____) 3. A. which B. who C. what D. where
(____) 4. A. dress B. drink C. drive D. tree
(____) 5. A. think B. mouth C. there D. thank