as low as :

as+形容词+as
as...as意为"和……一样"，表示同级的比较。使用时要注意第一个as为副词，第二个as为连词。其基本结构为：as+ adj./ adv. +as。例如：

(1)This film is as interesting as that one.这部电影和那部电影一样有趣。

(2)Your pen writes as smoothly as mine.你的钢笔书写起来和我的一样流畅。

其否定式为not as/so +adj./ adv. +as。例如：

This dictionary is not as/so useful as you think.这本字典不如你想象的那样有用。

若有修饰成分，如twice, three times, half, a quarter等，则须置于第一个as之前。例如：

Your bag is twice as expensive as mine.你的袋子比我的贵一倍。

since:

译作“自从…以来”
(1)接时间点：如 I have stayed in that country since 1995. 要求：谓v.用现在完成时，而且须是延续性动词。
(2)接一段时间 + ago：
如 They have lived in that house since two years ago. 要求：谓v.用现在完成时，而且须是延续性动词。
(3)接时间状语从句：
如 I have loved her since I met her last time. / Lily has stayed at home since she left school.
要求：主句的谓v.用现在完成时，而且须是延续性动词；从句的谓v.用一般过去时，而且须是终止性动词。
(4)用于句型“It’s / It has been + 一段时间 + since + 时间状语从句”中，译作“自从…以来, 已经…”。
如 It’s / has been three months since he moved to this city.
要求：主句的谓v.用一般现在时或现在完成时；从句的谓v.用一般过去时，而且须是终止性动词。
(5)用于句型“一段时间 + has passed since + 时间状语从句”中，译作“自从…以来,…(时间)已经过去了”。 Three months has passed since he moved to this city.
要求：主句的谓v.用现在完成时，而且动词必须是has passed；从句的谓v.用一般过去时，而且须是终止性动词。
(6)注：当since用于否定句时，主句的谓v.可以是终止性动词。
如 He hasn’t seen the film since last month.
(7)相关词组：“从那时起”：ever since、since then、from then on.
注：ever since作为一个词组，放句尾可单独使用。如I have given up smoking ever since. 另外，还可在since后接句子。since前加ever，只是加重语气而已。
如 I have given up smoking ever since I caught a bad cough.
(8) since还可引导原因状语从句，译作“由于；因为”，相当于because。如 Since he was lazy, he didn’t finish his homework.