The first stage involves growing a layer of real skin around a sample of the bulletproof skin, which takes about five weeks.

第一阶段的实验需要在防弹皮肤的样本周围培养出一层真正的皮肤，这需要大概五周的时间。

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The first stage in an audit involves asking whether the organisation deserves to be considered at all: is it a real not-for-profit agency, committed to the relief of suffering?

ECONOMIST: Humanitarian aid: Weighed and found wanting | The

The first stage of the application process involves groups setting out their aims and "vision" for the school and the area they hope to serve as well as showing demand from parents.

BBC: Teachers are half of free school inquiries