"生拼硬凑地写出" can be translated into English as "to cobble together (something written)" or "to piece together (something written) in a forced or haphazard way".
Here, "cobble together" is a colloquial expression meaning to assemble or create something hastily or from available parts, often implying a lack of refinement or coherence. "Piece together in a forced or haphazard way" more explicitly conveys the idea of assembling something with effort but without a natural or logical flow, which aligns closely with the Chinese phrase's connotation.
For a more concise and commonly used expression, "to cobble together (something written)" would be a suitable choice.