The responses of respiration to hypoxia is diphase,that is respiratory excitatory at first,then respiratory depression.

呼对缺氧的反应都是双相的,即先兴奋后抑制。

The drugs work well at first but gradually lose their effectiveness.

些药的效果起初非常好，但后来逐渐失效。

At first, the drug does no harm, but cumulatively its effects are bad.

药开始对人没有害处，但连续服用后果就坏了。

At first she was very nervous about making the crossing in such stormy weather.

一开始她对在样的暴风雨天气横渡颇为紧张不安。

At first I enjoyed all the parties, but the novelty soon wore off.

起初我喜欢参加一切聚会, 但种新奇感很快就消失了。

At first she threatened to dismiss me, but later she relented.

起初她威胁要解雇我, 但后来她态度软了。

He made progress in fits and starts at first but now he’s improving rapidly.

开始时，他的进步时断时续，但现在提高得很快。

In this paper, at first, the author discussed the geologic setting of uraniferous migmatite.

含铀混合岩大部分位于古陆隆起带边部、NW向花岗岩外接触带。

At first, he thought he had mistaken the address.

一开始他以为地址搞错了。

He was called a crank at first.

一开始他被叫做思想怪异者。

The new law about safety belts in cars was difficult to enforce at first.

规定系汽车安全带的新法规开始时是很难实施的。

He was cross at first, but later he relented.

他起初很生气,后来变温和了。

Under interrogation, he refused to say anything at first.

一开始审问的时候，他什么也不说。

At first hearing I didn't like the music.

第一个音乐时, 我不喜欢它。

Rather quiet at first, she grew very talkative over her second glass of sherry.

一开始她相当沉寂，但在喝第二杯雪利酒时她开始变得非常健谈。

Beethoven at first dedicated his Heroes Symphony to Napoleon.

最初贝多芬把他的《英雄》交响曲献给了拿破仑。

At first he was most dictatorial and aggressive in what he said,but when he realised that he would get nowhere by that means,he began to sing another tune.

起初他的说法十分专横武断,但当他认识到样做行不通的时候,他就开始改弦易辙了。

It was shown that the curing process of resoles, at first, proceeded by condensation reaction of methylol groups, and the formation of dimethylene ether linkage was predominant.

结果表明热固性酚醛树脂的固过程,首先是羟甲基发生缩合反应,缩合反应形成醚键是主要的。

I found it difficult to organize the timetables at first, but now I’ve got it down to a fine art.

开始的时候我觉得很难安排好时间表，但现在已经驾轻就熟了。

Feodal porter Ma Babei never reconciles to failure and buys off workers at first and then makes destruct insanely.

他先是收买工人，继而又疯狂进行破坏。