（deep）　 The project would ________the river from 40 to 45 feet,

（deep）　 The project would ________the river from 40 to 45 feet, to allow for larger ships.
【正确答案】：deepen
【题目解析】：构词知识题。空格处前面是助动词would，后面是名词，显然空格处要填一个动词。deep是形容词，变为动词需要添加动词后缀-en。因此正确答案是deepen，表示“加深”。