1. Conditional sentences are sentences that express one thing contingent on something.
2. There are four different types of conditional sentences in English.
3. Conditional sentences Type 1: If + S + V/ V-s / V-es, S + will + V-inf.
                                              Type 2: If + S + V-past, S + would/could/might + V-inf.
4. A compound noun is a noun made by putting two or more words together to act as one noun. 
    Examples of compound nouns are like washing machine, boyfriend, dining-table, public                    speaking, greenhouse...