烟草花叶病毒的核酸是（）。 A.DNA B.RNA C.DNA或RNA D.DNA和

下列词语中加粗的字，每对的读音完全相同的一组是[ ]

A．挣扎/挣钱     标识/识别    强压/强求     模具/机械模仿

B．滑稽/稽首　 伺候/窥伺    着实/着魔    悄悄/悄寂无声

C．沙砾/闪烁     希冀/羽翼    须臾/谀辞     拔擢/ 耀武扬威

D．收讫/迄今     强劲/劲风    濡染/蠕动     懈怠/百战不殆

如图，用100牛的力把一个重为10牛的物体压在竖直墙壁上，物体处于静止状态，这时物体受到的摩擦力大小为______N；当压力减为50牛时，物体沿竖直墙壁匀速下滑，则物体下滑时受到的摩擦力大小是______N．

TCP/IP （） layer protocols provide services to the application （） running on a computer. The application layer does not define the application itself, but rather it defines （） that applications need—like the ability to transfer a file in the case of HTTP. In short, the application layer provides an （） between software running on a computer and the network itself. The TCP/IP application layer includes a relatively large number of protocols, with HTTP being only one of those. The TCP/IP （） layer consists of two main protocol options—the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

The TCP/IP （） layer consists of two main protocol options—the Transmission Control Protocol (TCP) and the User Datagram Protocol (UDP).

A．application

B．session

C．physical

D．transport

海龙燃油宝分为（）两种。