He grew a different crop on the same field five years in a row, what researchers call crop rotation.

他连续5年在同一块地上轮流种植不同作物，研究人员称之为轮作。

《柯林斯英汉双解大词典》

The very first 911 call was made on February 16, 19 in Alibama.

第一个911报警电话是19年2月16日在阿里巴玛拨打的。

youdao

In theory I'm on call day and night.

理论上，我不分昼夜随叫随到。

《柯林斯英汉双解大词典》

And scientists are reporting this week on what they call the "indirect costs" of a virus-resistance gene in Cucurbita.

VOA: special.2009.10.27

There were fierce battles in Gaza on Friday as Hamas and Israel both rejected a United Nations call for an immediate cease-fire.

VOA: special.2009.01.10

For the next 12 hours, the medevac teams and machines will be on call to evacuate wounded troops from anywhere in eastern Afghanistan to Bagram's military-run trauma hospital.

VOA: standard.2010.04.27

Last year the convention center jettisoned about a dozen supervisors and placing 23 of its 44 full-time events workers on a call-in-as-needed status, all part of an effort to slash operating costs and free up tax revenue that the city of Minneapolis might use elsewhere.

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In the study, one on-call paediatrician was questioned in every hospital providing acute in-patient care for children.

BBC: Doctors 'miss' underweight children, UCL study suggests

Before urgent surgeries were squeezed in by whichever on-call surgeon had a break in the action.

FORBES: Special Surgery