题干
On the bank of the river, we found him ________ on the beach, with his eyes _____ on a kite in the sky.
A：seated; fixing
B：sitting; fixing
C：seated; being fixed
D：sitting; fixed
答案(点此获取答案解析）
D
=2x＋1250，若用水量为 50kg时，预计的某种产品的产量是