Full of form BC is Before Christ. Some also use BCE which stands for Before Common Era. Both mean the same.

ah,you have said such a deep thought.

It seems you are too scared to speak English. just think that the person you are talking to is an amateur in English. your fear will vanish automatically. And if that does not work then keep your hands on your heart and say all is well.

it means to forgive

A simple sentence contains one finite verb. A complex sentence contains more than one finite verb and the two clauses are joined by a sub ordinating conjunction. A compound sentence contains more than one finite verb and the two clauses are joined by a co ordinating conjunction.

Meaning of mourn is to express great sadness over something especially someone's death. Eg:-Today,they mourned the death of their colleague. Synonyms:-agonize,be brokenhearted,lament etc.

house is the residence of someone other than you. home is the residence of your own.

he was laughed at by all the students.

both are correct but 'till' is more ear soothing

yes they are difficult but not impossible. You can do anything provided you do not give up.