My grandpa sowed the flower seeds in the garden ______it was the best time for them to grow．

A．where

B．when

C．that

D．until

润滑油站的操作控制：1）油温一般控制在（）之间；2）供油压力一般控制在（）之间；3）当滤油压差大于（）时应及时转换过滤器或清洗滤芯。