China cut mortgage rates and downpayment levels for some home buyers on Tuesday for the first time since the 2008 global financial crisis, making one of its biggest moves this year to boost an economy increasingly threatened by a sagging housing market. Yet some analysts cautioned investors against thinking that the housing market and broader economy were poised to stage a stunning recovery. The housing downturn has weighed on already soft demand in China, dampening consumer confidence and slashing demand for related products from home appliances to glass, cement and steel.