as a rule 托福

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”肺丝虫侵，并不因肺丝虫侵立即发生流感。

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

根据经验算一下，每12平方米墙面需要一升涂料。