US President George W. Bush took a front-row seat at a church service Sunday, sending a quiet signal to China's leaders that they should expand religious freedom in this communist nation. "It wasn't all that long ago that people were not allowed to worship openly in this society," the president said after the hour-long service. "My hope is that the government of China will not fear the Christians who gather to worship openly. A healthy society is a society that welcomes all faiths." In a day of talks, the president was expected to trumpet a trade concession from China. He also was to prod Chinese leaders about currency system changes, human rights and the piracy of American movies, computer programs and other copyright material. Bush also was seeking China's cooperation on North Korea, Iran, Syria and other trouble spots.