We know a lot about these early years of European settlement because most migrants ________ with their families and many of their letters still survive.

He glanced at the note，_______andwent on with the meeting

Look! The man at the gate ____ be our headmaster. He is always standing there every morning.– No, it _____ be him. He is holding a meeting in the office now.

It never _____ humans until the mid­1990s that some animals can be cloned

I will carry out the plan _____ there is much difficulty ahead.