下列各句中，表达得体的一句是（ ）

_ his return from America, he got down to hisresearch

Success in life doesn’t happen __________It’s the result of devoting your time and energy to what you’ve set out to do.[ ]

When will the railway that connects the two cities open— next year. Only two thirds been built.

“Overall，export performance will bebetter，and it’s going to accelerate in theMonths.” said an economist in HongKong．