authenticate (v.) proof that something is real or true 认证

[例]  You should ask a skilled attorney to authenticate the signature at the bottom of this document in case that it is a forged one.

[同义词]  certify

average 1. (n.) the number which is calculated by adding several figures together and then divided by the number of figures均数
　
[例]  The sales average has been around 250 units.

[同义词]  mean

2. (adj.) middle平均的

[例]  the average price

averaging (n.) trading shares from the same company at different prices at the same time 股票平均买卖法

[例]  Average can maintain the price of a security.

awareness  (n.) being conscious of something知道

[例]  He has no awareness about the transaction.