You can use whether or if interchangeably in indirect questions. "If� is more informal and more common in spoken English. "Whether" is more formal and should be used in formal writing.

Do you know if/whether he has a girlfriend?

Could you tell me if/whether the supermarket is open on Sundays?

I was wondering if/whether you'd like to join me for lunch.

There are some cases where we MUST use whether:

Before infinitives (to + verb)

I don't know whether to tell him or not. or I don't know if I should tell him or not.

She's trying to decide whether to travel or continue her studies. or She's trying to decide if she should travel or continue her studies.

After prepositions (about, on, over, etc.)

We're thinking about whether we'd rather go out or stay in tonight.

It depends on whether it'll be rainy or sunny.

Always use if to introduce a condition, in a conditional sentence:

My boss gets mad if I'm late for work.

(Condition = I'm late for work. Result = my boss gets mad)

If you drive me to the airport, I'll give you $15 for gas.

(Condition = you drive me to the airport. Result = I'll give you $15)

I'd surf every day if I lived near the beach.

(Condition = living near the beach. Result = surfing every day)

If we'd left home earlier, we wouldn't have missed our flight.

(Condition = leaving home earlier. Result = not missing the flight)

Rules to play Soccer

Know the grounds for a yellow card

A referee issues a yellow card as a warning to a player. Two yellow cards result in a red card, after which that player must leave the game permanently. Reasons for yellow cards includeDangerous play. High kicking near a players head, for example. Illegal obstruction. This happens when a player intentionally takes a position between and an opponent when that player isnt within playing distance of the ball. Charging the goalkeeper in the goal area. Goalkeeper playing the ball with his hands when the ball is kicked by a teammate.Goalkeeper Infringements. Unsafe play such as charging the goalie.Goalkeeper taking more than four steps while controlling the ball. Intentionally wasting time at the end of a game.