sogo trade? have not heard before. why don't you open a U.S. brokerage account directly with the broker in U.S.? If you use 3rd party brokers, you will be charged a hefty commission rate
You can try www.interactivebrokers.com they have an Asian hub in HK.
You can use that broker to trade U.S. stocks, ETF and options

"Dow tumbles in early morning trading"
As usual, not surprised if we had another round of bad news for market to crash again, hopefully to make a 'successful test of the lows'
Becareful of going long in U.S. stocks. After all we are in a bear market right.
The market had rallied up so much for the past weeks. Not worth to buy call options now. Might consider to buy some put options

Beware guys, the US stock market is going up on low volume. That means professional money has stayed sideline and did not participate in the up move. When they have finish distributing to the public, then all the market needs is some surprise news to sent the stock market down again

By the way tonight have FOMC news which will rock the markets again

Cool.... Did you watch how the U.S. stock markets plunge right after the FOMC news few days ago? Also Crude Oil just drops like a bomb USD sky rocketed and GBP EUR drops like no tomorrow hehe.