David 手冊 Hebei Xiaowopu world habitat awards rammed earth building 2020 chairman sung bailey bridge manual design footbridge COVID-19 Yunnan video xiaowopu 2018 2019 WZQ_ChitChitCorner interview shaanxi macha sharing gansu leadership sir_david hebei Gansu rammed_earth Interview photo_competition BRIDGEWITHSOULS bailey_bridge press_conference workshop activity project greetings 2021 investagation volunteer_service serveHK newsletter local_volunteeing WZQ_AMemoryJourney ceremony Building with Earth Macha village Terrafibre Award annual review activity review covid19 2022 community_enrichment Wooden stool mui tsz lam Mui Tsz Lam wooden stool book fair 2022 Discover the Other Side of the World International Youth Day Design Thinking Workshop Lantian Theater Medical Student F山u Tei Au Tsuen HSU WZQ Fu Tei Au Tsuen The University of Hong Kong Enrichment Year Exhibition UST WZQm bailey bridge exhibition Tongji university gold medal Shanghai Social Organization Public Welfare Entrepreneurship Competition Coordination Council chinanews youth development wuzhiqiao HKU bridging hearts sustainable development climate change market Endless Learning board retreat bailey bridge workshop youth committee