There must be someone present when cleaning the office; otherwise it is not allowed to do any cleaning work.

必须在办公室内有人时才可做清洁；否则清洁工作是不被允许的。

youdao

Wear cotton gloves when cleaning silver, because the acid in your skin can tarnish the metal.

清洁银器时要戴上棉手套，因为你皮肤里的酸性物质会使它失去光泽。

youdao

A good tip when cleaning out your closet: Ask a friend whose style you admire to come over and help.

清理衣柜的窍门：叫一个品味你喜欢的朋友来帮你。

youdao

His mother worked cleaning the homes of white people when she could.

VOA: special.2009.11.01

Wear a filtering mask when cleaning to avoid inhaling dust or airborne particles from cleaning products.

CNN: Sore throat

The landlord of the Victory Inn at Porthtowan found the live device when cleaning out the fireplace.

BBC: Live bomb found in Porthtowan pub fireplace

Rules govern how many hamburger patties to a pound of beef (10), how long to toast a bun (17 seconds) and how much sanitizer to use when cleaning the shake machine (1 packet for 2.5 gallons of water).

FORBES: You Want Data With That?