However, the things that are extremely hard in HDBMS (all but a very limited few) are only moderately hard in an RDBMS.

不过，在HDBMS中极其困难的事(几乎非常少)在RDBMS中的难度只是中等。

youdao

First, I am training hard now swimming seven and a half miles a day. Prior to that time I also kept physically fit by training moderately hard.

首先，我训练刻苦——现在每天游泳七英里半，在那以前我也通过适度刻苦训练保持身体健康。

youdao

First, I am training hard now swimming seven and a half miles a day. Prior to that time I also kept physically fit by training moderately hard.

首先，我训练刻苦——现在每天游泳七英里半，在那以前我也通过适度刻苦训练保持身体健康。

youdao