	(1)	(2)	(3)	(4)
	chengben1	chengben2	chengben3	chengben4
VARIABLES	lnexport	lnexport	lnexport	lnexport
				
DDD	0.2131***	0.2119***	0.2508***	0.2455***
	(0.0815)	(0.0815)	(0.0898)	(0.0878)
treat_year03	0.1078*	0.1001	0.0448	0.0247
	(0.0647)	(0.0628)	(0.0643)	(0.0647)
水运成本DD	0.0388*	0.0390*	0.0099	0.0092
	(0.0232)	(0.0233)	(0.0204)	(0.0199)
DD	-0.2583***	-0.2574***	-0.2612***	-0.2460***
	(0.0767)	(0.0767)	(0.0842)	(0.0824)
lnage			0.1927***	0.1959***
			(0.0317)	(0.0328)
lnsize			0.5529***	0.5592***
			(0.0257)	(0.0261)
lnlabor			0.1539***	0.1628***
			(0.0145)	(0.0154)
profit			0.8869***	0.8718***
			(0.0677)	(0.0722)
lngdp			-0.0016	-0.0019
			(0.0188)	(0.0194)
openness			-0.0066	-0.1416
			(0.0397)	(0.0938)
lnpeople			-0.0179	-0.0157
			(0.0376)	(0.0393)
lnrailway		-0.0310	0.1079	0.1238
		(0.0707)	(0.0788)	(0.0794)
lnhighway		0.0980	-0.2382**	-0.2138**
		(0.0893)	(0.1001)	(0.1031)
Constant	14.0175***	13.1599***	8.6231***	8.2360***
	(0.0288)	(1.0430)	(1.2431)	(1.2456)
				
Observations	159,010	159,008	128,640	119,795
R-squared	0.796	0.796	0.810	0.810
Robust standard errors in parentheses				
*** p<0.01, ** p<0.05, * p<0.1				
