2 sentences

1. 胚胎在孕期第四周开始成形。

   pēi​tāi zài yùn​qī dì​sì zhōu kāi​shǐ chéng​xíng.

   The embryo begins to take shape in the fourth week of pregnancy.

   Source: Dong Chinese Dictionary

2. 这种塑料在模具中加热后，很快就能成形。

   zhè zhǒng sù​liào zài mú​jù zhōng jiā​rè hòu, hěn kuài jiù néng chéng​xíng.

   This kind of plastic takes shape quickly once it is heated in the mold.

   Source: Dong Chinese Dictionary