News At Seven-Thirty highlights: Corrosive liquid dropped onto Mong Kok street; White House offered temporary help to Big Three; Unrest in Greece spread to other parts of Europe; Inquest on killing a Brazilian by British police; Severe storms flooded Rome; MTR driver suspended from duty over human error; Using natural gas as bus fuel studied; Gov’t investigating cause of outbreak in Yuen Long; HK Brands and Products Expo attracted thousands; Annual horse auction with lower sales price.