简述扫描仪的主要性能指标。
下面哪一项不是消化液的生理作用（） ["水解食物中的大分子","为消化酶提供适宜的pH环境","稀释食物，使其渗透压与血浆相近","保护消化道粘膜","有时会损伤消化道粘膜"]
按媒介划分，广告设计形式种类有（） ["广播广告","印刷广告","户外广告","POP广告"]
What is periodically sent by a DIS on a LAN to ensure that all adjacent neighbors' IS - IS link - state databases are synchronized?（） [" complete SNP (CSNP)"," partial SNP (PSNP)"," database query"," database description packet (DDP)"," link - state summary"," hello"]
细度指的是小于（）毫米煤样占所有煤样的百分比。 ["1","3","5"]
党内政治生活的“四性”是指：（）、（）、（）、（）。
