as a rule 托福

As a rule of thumb you need a litre of paint to every 12 square metres of wall.

根据经验粗算下，每12平方米墙面升涂料。

As a rule the swine infested with the lungworms carrying the "masked virus" did not develop swine influenza immediately upon infestation with the lungworm.

通常，受到携带了“隐蔽病毒”的肺丝虫侵袭的，并不因肺丝虫的侵袭立即发生流感。