the moment引导时间状语从句时前面可以加介词吗

比如下面的句子，the moment 引导时间状语从句，相当于 as soon as：

The moment I have finished I’ll give you a call. 我一干完就给你打电话。

The moment he spoke we recognized his voice. 他一说话，我们认出了他的声音。

The moment I saw him I knew that there was no hope. 我一看到他，就知道没有希望了。

请问这样用的the moment前面可以加介词吗？比如说成：

At the moment I have finished I’ll give you a call.

At the moment he spoke we recognized his voice.

At the moment I saw him I knew that there was no hope.

解答如下：

如果要当作连词使用，不可以加任何介词，也不能再加任何连词，因为The moment 本身就属于短语连词，引导时间状语从句。

（特别备注:如果加了介词at 就不再是连词，而是一个介词短语at the moment。 意思是“ 当时；此刻，现在，目前”)

at the moment :此刻, 现在, 目前, 当时 

The police arrived right at the moment of the explosion. 

警察就在爆炸的那个时候赶到了。 

I was writing a letter at the moment when he came in. 

他进来时我正在写信。

英语中引导时间从句的连词有一类是由名词短语转化而来的，由这类连词引导的时间状语从句，一般表示主句的动作与从句的动作立即相随而发生。使用这些短语连词时，一般不再加其他的连接词。

(1)by the time 到……的时间

By the time he was fourteen years old, he had learned math all by himself.

到14岁的时候，他已经自学了数学。

The truck will have arrived by the time you have all the things packed up.

等你们把所有这些东西包装完毕时，卡车将已经抵达。

(2)each time/every time 每次……

Each time I meet an Englishman, he starts off the conversation with

some comment on the weather.

每当我遇到英国人时，他的谈话总是以议论天气开始。

Every time I call on him ,he is out.

每次我去拜访他，他总是不在。

(3)the first time 第一次……

He had impressed me that way the first time I met him.

我第一次碰到他时他就给我这个印象。

(4)next time 下一次……

Next time you come in, please close the door.

下一次你进来时，请关上门。

(5)the moment (or the minute, the instant)一……就

The moment I saw him I knew that there was no hope.

我一见到他就知道没有希望了。

I recognized you the minute I saw you.

我一看见你就认出你来了。

I sent you the news the instant I heard it .

我一听到这个消息就让人给你送去了。