下面可作为食品添加剂酸味剂的又不能加入食品中的是（）。A、富马酸 B、苹果酸 C、盐

对重的计算公式为()

A.W=G+（0.2～0.3）Q

B.W=G＋（0.4～0.5）Q

C.W=G+（0.3～0.5）Q

D.W=G-（0.4～0.5）Q

Nearly 90 percent of the young people in our country use the Internet, but about half of them use them every day. They visit chat rooms and sending e-mails. More and more scientists has begun to wonder: Is the Internet good or bad for kid? Some of them think what it is impossible to answer that question because the Internet has so much things. What’s more, recently studies show the online world can be helpful at some ways and dangerous as well. It can be both an educational resource and hiding place for bad people.

用于显示部分查询结果的TOP短语，使用时需与之连用的短语是（ ）。

A． if(x＞0)y=1　　　else if(x＜0)y=-1;　　　else y=O；

B． if(x)　 if(x＞0)y=1；　　 else if(x＜0)y=-1；

C． y=-1;　　if(x)　　if(x＞0)y=1；　　else if(x＝=0)y=0；　　else y=-1；

D． y=0；　　if(x＞=0)　　if(x＞0)y=1；　　else y=-1；

人工心脏起搏器编码的第4个字母代表

A．起搏的心腔
B．感知的心腔
C．感知后的反应方式
D．程控、遥测、频率应答功能
E．抗快速心律失常功能

以温和噬菌体为媒介，将供体菌DNA的片段转移给受体菌，并使受体菌获得新的遗传性状的过程被称为______。