展开 (zhǎn kāi) means both 'to unfold/spread out' (a physical object like a map) and 'to launch/carry out' (an activity, discussion, or project). It is more concrete than 开展 (kāi zhǎn), which is used almost exclusively for abstract activities (e.g., 'conduct research'). 展开 also contrasts with 张 (zhāng), which is a verb for opening flat objects (e.g., open a mouth, spread a sheet) but never used for launching activities.