African countries frequently have to wait for years, if not decades,for new medical products to trickle into their health systems.

VOA: special.2011.01.19

There are not many countries in which, for instance, ; that sort of religious challenge, say, to science; it happens more frequently in this country.

比如说，很少由国家，那里宗教对科学造成的威胁;,比美国还要频繁。

普林斯顿公开课 - 人性课程节选

This is a signal - this passing of phosphorous - is a signal that's used very frequently in intracellular communication.

这是一种信号,一种通过磷酸来传递的信号,这种信号在细胞内通讯时经常被用到

耶鲁公开课 - 生物医学工程探索课程节选

These interpretations are not always clear and frequently do not always clear and frequently do not address the specific program contemplated.

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Coinage fluctuated between all gold (less frequently) or all silver (more frequently) or all paper or all Spanish for the dollar.

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In the late 1960s and early 1970s programmes intended to help the poor were frequently unsuccessful and even more frequently unpopular.

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