植物生长需要多种无机盐，其中需要量最多的是含下列哪项的无机盐？[ ]
A．铁、镁、钙
B．氮、磷、钾
C．氮、铁、锌
D．硫、锌、硼
答案：B
Chinese people arc supposed to __________ their bowl of rice when they cat.[ ]
A. pull down
B. put up
C. pick out
D. pick up
我国志贺菌中感染居多的是
A．痢疾志贺菌B．鲍特志贺菌C．福氏志贺菌D．沙氏志贺菌E．宋内志贺菌
