about" position", what means in this sentence? The top of the computer monitor should be slightly below eye-level and it should be positioned to avoid any type of glare. be positioned to: what exactly means?

what is that mean: Never brace your wrists against mouse pads when you are typing what is that mean: Never brace your wrists against mouse pads when you are typing

what is that mean:"The earlier dilution of effort was made worse"? The earlier dilution of effort was made worse as the german air force wandered between attacks on transport, civilian morale and the aviation industry.

i dont know what the sentence means when the children started kindergarten they were still tested in the bottom one percentile on the lower test of basic skills. in the bottom? what bottom? one percentil? what means?when the children started kindergarten they were still tested in the bottom one percentile on the lower test of basic skills. what means ?

one of the things is want have? or one of the wants is have? One of the things that the president wants in his education plan is for Head Start to have an academic goal along with social.One of the things that the president wants in his education plan is for Head Start to have an academic goal along with social well...what means about this sentences?

A multiple-choice question！Why the right is C, not D,is these the same meaning?? TEXT: A pollution clean-up will be partly to blame for such a temperature rise.A reduction in emissions of sulphur dioxide,which causes acid rain, has increased the impact of greenhouse gases.These gases trap the sun's heat whereas sulphur dioxide cools the atmosphere. Question: "what should be blamed for the temperature rise ?" [A] Global warming. [B] Storms,floods and droughts [C] A pollution clean-up [D] A reduction in emissions of sulphur dioxide.

what time use "wheelchair",and ,what time use "wheelchairs" a lot of word I found this situation, wheelchairs has two wheels ,right？but sometimes it use wheelchair ,and sometimes it use wheelchairs ,it confuse me complelely. please tell me why?

“on board the aircraft” and ”on the plane" ,what different between them? they looks as the same meaning ,but ,what different between them in English?

Infants under the age of two on the date of their return flight have no allowance. what means??