在从莫斯科飞往北京的飞机上，中国人甲与俄罗斯人乙发生争吵，情急之中，甲用饮料瓶将乙打

内因火灾多发生在（）、巷道两侧受地压破坏的煤柱、巷道中堆积的浮煤或片帮冒顶处、与地面老窑的连通处。

为什么生长因子通常是维生素、嘌呤、嘧啶及氨基酸等，而葡萄糖通常不会作为生长因子？

纯粹接触假说

长期偏食某种食物，会导致某些“毒性”成分在体内（）。

A、聚集

B、扩散

C、蓄积

D、丢失

In the following essay, each blank has four choices. Choose the most suitable one from the four choices and write down in the answer sheet. There are two types of key technology: private key and public key. Private-key encryption methods are called (71) ciphers, information is encrypted with (72) both the sender and receiver hold privately. Public-key encryption methods are called (73) ciphers, (74) created for each user, encryption key and decryption key are (75)

A．synchronous

B．Asynchronous

C．symmetric

D．asymmetric