Inventions and discoveries

We use the ________ to say that something heppened before another action or event or event n the past.

• present progressive

• simple past

• past perfect

Dr. Spencer realized the microwaves had melted the chocolate. The first event is:

• had melted

• realized

Dr. Spencer put popcorn in front of the magnetron because he had seen the chocolate melt.

The Second event is:

• had melted

• put

When Dr. Spencer got his first job in a factory, he had just finished 5th grade at school.

What is the 1st. event?

• got

• had finished

Before Dr. Spencer made his discovery, people hadn't used microwaves. What is the 2nd. event?

• made

• hadn't used

The past perfect of the verb freeze is:

• had froze

• had freezen

• had frozen

The past perfect form of the verb leave is:

• have left

• had left

• had leave

The past perfect form of the verb send is:

• had sended

• had send

• had sent

When Howard Carter _______ the tomb, he _________in Egypt for 31 years.

• found // had worked

• find /// worked

The simple past tense of the verb make is:

• made

• maked

• makes