Yes it is important, but take note, a country can stand alone without having English as their second language. There are successful countries whose people do not use English, they prefer to use their native language for their daily communication.
It depends upon the capability of a person, If He/She is capable of having a multiple languages then He/She can obtain more languages.
Polish is now the main language spoken in England after English, according to 2011 census data released by the Office for National Statistics on Wednesday. The first ONS language figures, recorded from a survey of 56.1 million residents of England and Wales, show 546,000 speak Polish
The second-most common language spoken in the U.S. is Spanish. But if you look at the most common languages after English and Spanish, the results get a little more surprising, especially when you parse them by state.
For me, the spoken language in most countries in the world is English.
the predominance of english in many sectors such as world trade technology and science has contributed to english speaking societies.
1. Overuse of adverbs 2.Too many prepositional phrases 3.Ambiguous modifiers 4.Misuse of lie/lay 5.Ambiguous pronoun references 6.Comma splices 7.Run-on sentences 8.Wordiness
They will know through studying their lesson. Therefore, I would say, it is necessary for them to read their lessons everyday and study the important points.