起征点是指征税对象达到一定数额才开始征税的界限，征税对象的数额达到规定数额的，只对其

慢性支气管炎与肺结核的主要鉴别依据是

A．发热
B．咳嗽
C．咯血
D．肺部啰音
E．痰液检查

哪个删除操作不正确

A．从雇员信息表emp中删除行('010'，'王宏大'，'01'，'1200')

B．从部门信息表dept中删除行('03'，'服务部'，'02')

C．从部门信息表dept中删除行('04'，'财务部'，'04')

D．先在雇员信息表emp中删除行('010'，'王宏大'，'01'，'1200')，然后从部门信息表 dept中删除行('01'，'业务部'，'01')

Some of the keys have a special use. There are referred to as command keys. The 3 most common are the Control or (66) , Alternate or (67) and the Shift keys though there can be more (the Windows key for example or the Command key). Each key on a standard keyboard has one or two characters. Press the key to get the lower character and hold Shift to get the upper. Disk Drives - All (68) need a drive to get information off - or (69) - and put information on the disk - or (70) . Each drive is designed for a specific type of disk whether it is a CD, DVD, hard disk or floppy. Often the term ’disk’and ’drive’are used to describe the same thing but it helps to understand that the disk is the storage device which contains computer files-or software - and the drive is the mechanism that runs the disk.

A．sets

B．dishes

C．disks

D．panels

物流活动中能体现生产者、采购者、物流作业者与销售者之间关系的是流体的 ( )。

A．自然属性

B．社会属性

C．市场流向

D．计划流向

果蝇是遗传研究的常用材料。请分析回答

若图甲所示的原始生殖细胞经减数分裂产生一个基因型为aXBXB的生殖细胞，则发生这种情况的时期最可能是（），此细胞发生了（）变异。