11.   But some economists said there is still a real chance the central bank could tighten monetary policy.

12.   Central banks might then need to tighten policy.

13.   Despite the lopsided votes on the border security bill, Congress had difficulty deciding how much to tighten immigration policy.

14.   Faced with this truism, a prudent central bank would have tightened policy more aggressively by now.

15.   For one thing, the Fed has tightened monetary policy substantially in the last year.

16.   Greenspan gave little guidance, though, about whether the central bank would tighten policy further later in the year.

17.   He added that the firm had recently tightened its policy and would register only when it actually did lobbying.

18.   He said the Federal Reserve could probably not ignore such a low unemployment rate and would raise rates again this month but could then stop tightening monetary policy.

19.   If anything, people are now factoring in some fear that the Fed will tighten monetary policy.

20.   If the employment numbers for March are strong, the Fed may be more likely to continue tightening monetary policy.