男性，7岁。诉下颌前牙松动。口腔检查见：松动Ⅲ度，牙冠有深龋_爱下问搜题

搜题请搜索小程序“爱下问搜题”

问题单项选择题

男性，7岁。诉下颌前牙松动。口腔检查见：松动Ⅲ度，牙冠有深龋洞，已从舌侧萌出，诊断（）

A．乳牙滞留

B．乳牙早失

C．乳牙根尖周炎

D．乳牙牙周炎

E．乳牙外伤

答案

参考答案：A

解答题

在下面的横线里填上“＜”“＞”或“=”．
3.48×0.99______3.48
2.50

1.2^2______1.2×2
5.2÷0.01______5.2×100．

单项选择题

(56) is a one-way function that takes an arbitrarily long piece of plaintext and from it computes a fixed-length bit string.

(57) is a protocol that most USENET machines now use it to allow news articles to propagate from one machine to another over a reliable connection.

(58) is an approach preferred by cable TV providers. In this solution the fiber terminates at an opto-electrical converter and the final segment is a shared coaxial cable.

(59) is a device used to connect two separate network that use different communication protocol.

(60) is a digital-to-digital polar encoding method in which the signal level is always either positive or negative.

（59）是（）

A.Router

B.Gateway

C.Bridge

D.hub