题目
Investigators have not determined what caused the head-on ___ of the two cargo ships. (collide)
Investigators have not determined what caused the head-on ___ of the two cargo ships. (collide)
题目解答
答案
根据题目要求，需将“collide”转换为名词形式“collision”以符合句式需求。完整句子为：
Investigators have not determined what caused the head-on collision of the two cargo ships.
“Collision”准确表达了“碰撞”之意，且符合“head-on”修饰的需要。
答案：collision