I sometimes find it a strain to be responsible for the mortgage.

我有时发现偿还抵押借款是个负担。

《柯林斯英汉双解大词典》

From other angles it seems to be under a Herculean strain, as if fighting to support the enormous weight of the cantilevered floors above.

从另一个角度看它又像是在施展大力神的应变力，想要努力支撑住上面的巨大的悬臂式底板的重量。

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But natural selection is a powerful force, and if the spread of the disease means they have to be used widely, a resistant strain of the virus could easily evolve.

但是自然选择是一种强大的力量，而如果疾病的传播意味着这些药物将被广泛使用的话，一种具有抗药性的病毒毒株可能将轻易地进化出来。

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World Health Organization officials say it could be months before a vaccine is available to treat this latest strain of flu.

VOA: standard.2009.04.28

"We had a new strain of flu. We did not really know that its lethality was going to be.

VOA: standard.2009.05.03

Hundreds of millions braved the cold winter weather to travel home to be with their families, putting a great strain on the country's transport system.

VOA: standard.2010.02.14

Within hours thousands of news services have been marking the geography of death and illness, pointing to an usually aggressive outbreak of what appears to be a rampant strain of E. coli.

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Hondo was thought to be carrying a side strain, and he bowled only six overs though apparently without restraint.

BBC: Zimbabwe beat plucky Dutch

If it turns out to be a non-resistant strain, you can then switch to the cheaper vancomycin.

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