PROVIDENCE, R.I. (AP) — President Donald Trump has called the country to open for business by mid-April, but some experts warn it’s not as easy as flipping a switch: Economies run on confidence, and that is likely to be in short supply for as long as coronavirus cases in the United States are still rising. Many public health experts have warned that the current restrictions should only be lifted gradually. They expect efforts to curb the disease will continue for several months at least. But many businesses are wary of reopening too soon. They are worried that could be seen as irresponsible. And even if they did reopen, would customers come if the virus isn’t under control?