toworkon,butIgotsotiredthatIcouldnolonger________.

Is this model plane yours,Susan?–Yes,it’s mine.It’s made by_________.

I am looking for information on social safety.—-You can take this book. Social safety is _______ introduced in it

We didn’t believe it ______ we saw it with our own eyes.

as Newton was, many of his ideas_______ today and are being modified by the work of scientists of our time.