Perfect tenses and inventions

Today, we __ (discover) the cure for many diseases, but we __ (find) a cure for the common cold.

The world ___ (benefit) greatly from the internet, which ____ (become) widespread by the early 2000s.

By the time we ____ invent, the first television, we already ___ (invent) the aeroplane.

In the next ten years, researchers _____ (develop) smarter robots than those we _____ (see) so far.

By 2000BC, the Egyptians and Chinese __ (invent) writing, but they __ (learn) how to print books.

By the time flying cars are common, engineers ____(solve) many safety challenges that ____ (limit) previous prototypes.

By 1900, the telephone __ (be invent), but the Wright brothers __ (yet make) their first flight.