一些初二英语问题He --------(write) a letter to his parents every two

有上下文吗?如果没有就应该是writes 因为every two weeks 是“每隔两周”的意思.“他每隔两周给他的父母写一封信”应该是经常反复发生的,要用一般现在时.
PS：如果是明确的过去的某段时间内,还可以用过去时,如：He wrote to his parents every two weeks when he was in the USA.