1.ever since也可以单独使用,意思是“自那时起”.
甚至连since都可以单独使用,意思也是一样的：ever since = since = since then = ever since then.
至于“那时”指的是什么时候,则要看上下文了.此处的确是指“自钟（多年前）被毁坏起”,即even since the clock was damaged many years ago.
当然ever since也可以加表示某一时刻的名词短语或时间状语从句.
2.can be中的can表示可能性.
一般来说,can表示可能性很少用于肯定句中,一般用于否定句/疑问句中.
只有当表示的可能性为客观情况时,才可以使用can.
如果表示说话人的主观猜测,则一般用may/might/must等.
如：Houses can fall down after an earthquake.
3.as stressed many times为状语从句的省略,即as stressed many time = as (+ 主句主语 + be +) stressed many times,意思应该翻译成“就像多次被强调的那样”.
如：The plan should be put into practice at once as (the plan was) stressed many times.
像多次被强调过的那样,这个计划（的确）应该立即实施.
4.因为此短语not being able to use a computer做句子的主语,所以用其动名词形式.
如果用not be albe to use a computer,则它是动词原形结构,无法做一个句子的主语.
5.此句为倒装句,正常句序为：Spending too much comes along with eating too much.
可翻译为：和饮食过多相伴而来的是开支过度.
此comes直译为“来临/到来”,可以理解成“产生/出现”.
6.这是if引导的条件状语从句的虚拟语气中,if从句出现的倒装现象.
如果是对将来动作进行虚拟,则if从句谓语可以使用should do sth,were to do sth或动词过去式,主句谓语使用would/could/might do sth.
即：If you should be fired,your health care and other benefits would not be immediately cut off.
而相关倒装语法规定,如果if从句出现should/were/had,则可以将其提前至从句句首,并省略if.
即：If you should be fired = Should you be fired.