Conclusions: In diabetic retinopathy, the changes in vascular morphology occur first, and the expression of growth factor follows.

Or services that the process invokes and invoke the process ( where either may occur first).

或者既由流程调用又调用流程的服务（首先出现哪种情况都有可能）。

Corpus-based study shows that chunks are universal and occur frequently in language.

基于语料库的研究表明，语言中普遍存在着重现率很高的语块。

However there remains a serious problem on school safety, Accidents occur frequently on campus.

然而，近年来，我国校园安全问题依然严重存在，校园安全事故频频发生。

Road traffic accidents occur frequently, which caused serious personal injury and economic losses.

道路交通事故频繁发生，给人们造成了严重的人身伤害和经济损失。

In recent ten years, accidents induced by fire and explosion occur frequently.

近十年来，国内外火灾和爆炸事件时有发生。

If such events occur frequently, the trace may significantly impede performance.

如果此类事件频繁发生，则跟踪可能会显著地降低性能。

Since the 1990s, the infringement cases occur frequently.

因而自上世纪90年代以来，商号权侵权案件即时有发生。

Such integration should occur frequently throughout the day.

这样的集成在一天当中应该频繁地进行。

Sudden public incidents occur frequently to China in the profound transition.

处于深刻转型期的中国突发公共事件频繁发生。

With the forest tourism develops rapidly, accidents occur frequently.

森林旅游迅速发展的同时，安全事故频频发生。

In this case, intellectual property infringements may occur frequently.

在这样的情况下，就很可能出现知识产权侵权情况。

Social problems and social conflicts occur frequently because China remains in the social transition.

中国正处于社会转型期，社会问题和社会矛盾频繁发生。

In recent years, campus PE Injury Accidents occur frequently.

近年来，我院体育伤害事故不断发生。

At the same time, the fire accidents occur frequently.

与此同时火灾事故也频频发生。

Conflict is one of social interactions that occur frequently between children.

冲突行为是儿童与同伴之间频繁发生的一种社会互动形式。

Claims occur frequently in international trade.

国际贸易中经常发生索赔现象。

In vehicle's normal running process, acceleration of starting occur frequently.

在车辆正常行驶状态下，启动加速是一个经常发生的过程。

But whether this will actually occur is an "incredibly complicated" question, said Dillon.

但是Dillon说，这是否会真正发生则是一个“极端复杂”的问题。

Catering supply, underwear product exhibit for sale.

经营范围：饮食供应，内衣产品展销。

Relationship fussing will, of course, occur but this is normally more a part of your lessons than karma.

激动关系，当然，发生，但是通常你们的课程与因果报应相比较这一部分是多余的。