依据施工合同示范文本规定，投料试车工作应在工程竣工( )。

A．验收后由发包人负责

B．验收前由发包人负责

C．验收后由工程师负责

D．验收前由工程师负责

Tourist excitement has built up _______ new places of interest were opened two years ago.

 [ ]

A. as

B. since

C. only if

D. even though