题目

 Johnson had made up his mind to give up, but on second thought became _________ to try a third time.      A. claimed     B. determined      C. declared     D. supposed  答案：B(1)打开汽水瓶盖时，汽水会自动喷出的原因是__________________________  (2)盐酸、硫酸、氢氧化钠溶液、氢氧化钙溶液能导电的原因是_______________________  (3)磷肥的作用是__________________________________  (4)水果蔬菜富含维生素，维生素在人体内的作用是____________________________