It stands for Old English.
Answer:
'He had left the house' can function on its own as a sentence. That's the independent clause. 'before mother arrived' cannot function on its own. it is a sentence fragment, or a dependent clause
The answer would be the third option, elusive. I hope this helped! :)
The shirt is a motercycle
That dosen’t really make since in English, the only thing I might have wrong is the last word.