Outbreaks among pigs normally occur in colder weather months ( late fall and winter) and sometimes with the introduction of new pigs into susceptible herds.

Based on the author's experience and understanding, this paper first analyses the errors that normally occur in library cataloguing and their causes and then proposes a number of countermeasures.

文章结合作者工作经验与体会，分析了图书分类工作存在的常见错误及产生的原因，并提出了相应的改进措施。

Evaporates normally occur in large-scale petroliferous basins in the world, so there exist closely relations between evaporates and petroliferous basins.

世界上许多大型含油气盆地都有蒸发岩分布，蒸发岩与沉积盆地的含油气性有着非常密切的关系。

Reduction in image quality will normally occur around the distance of3 meters and less with high-speed lenses.

使用高速镜头时，影象质量下降通常会发生在被拍摄主体位于三米以内。

Vortex-induced vibrations normally occur in the slender structure which has smaller damping.

涡激振动较易在阻尼较小的细长结构上发生。

Due to the globalization and virtual feature of network space, Internet privacy violations often occur.

由于网络空间的全球性和虚拟性，网络隐私权的侵权行为时有发生。

Such impromptu situations often occur when we are with master.

像这样临时起意的情况，在师父身边经常会发生。

Wall crack problem caused by temperature change and out of shape foundation often occur in mixed structure building.

砖混结构房屋常见的问题就是墙体裂缝问题，即由于温度收缩引起的墙体裂缝以及由地基变形引起的墙体裂缝。

So the errors often occur in calculation, test and subjective assessment of acoustics.

因此在计算、测试与音质的主观质量之间往往存在误差。

Gout attacks often occur without warning in the middle of the night.

痛风通常在半夜毫无征兆地发作。

Misunderstandings often occur in cross cultural communication.

跨文化交际过程中常常出现误解。

By the limitations of the existing road traffic, motor vehicle accidents often occur.

受现有道路交通的限制，车辆事故时常发生。

However, the postoperative complications often occur.

然而，肺癌术后并发症经常发生。

At the beginning of my internship, when these problems often occur.

在刚开始我的实习工作的时候，时常会出现这些问题。

Natural calamities often occur nearby golden section day between solar terms.

自然灾害多数出现在节气之间的黄金分割日附近。

Content abstract: complaints, is often occur in the hotel one word.

内容摘要：内容摘要：投诉，是酒店中常常出现的一个词。

Changes in job or communicative patterns often occur associated with this transit.

在此行运期，工作上的改变或沟通形式往往关联发生。

Quite amounts of accidents often occur in mining process.

煤矿在开采过程中，常常会发生很多事故。

Kinetic injuries often occur when students have their physical education classes.

在中学体育教学中，经常会发生一些运动性损伤。

In natural environment, sound signals often occur with background noise.

在自然环境中，声音信号常处于一定的背景噪声环境下。

In the construction process, engineering changes often occur.

建设项目建设过程中，常会发生工程变更。