Past Simple - Present Perfect

Exact Language for Lab Safety
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Slide 1: Slide
EngelsMBOStudiejaar 1

This lesson contains 22 slides, with interactive quizzes and text slides.

time-iconLesson duration is: 30 min

Items in this lesson

Exact Language for Lab Safety

Slide 1 - Slide

Here's the scenario.
You are working in a lab and have to heat a solution with a burner for exactly 30 minutes. After a while you ask your lab partner to check on it. They tell you one of the following sentences.

Slide 2 - Slide

Here's the scenario.
You are working in a lab and have to heat a solution with a burner for exactly 30 minutes. After a while you ask your lab partner to check on it. They tell you one of the following sentences.
A: The burner heated the solution for 30 minutes
B: The burner has heated the solution for 30 minutes.

Slide 3 - Slide

Slide 4 - Slide

Here's the scenario
A: The burner heated the solution for 30 minutes
B: The burner has heated the solution for 30 minutes.

One of these means you should rush to turn off the burner right now! Can you tell the difference between these sentences and explain why you should be worried?

Slide 5 - Slide

What are the differences between sentence A and B?

Slide 6 - Open question

A: The burner heated the solution for 30 minutes.
This means that the burner was on for 30 minutes and was then turned off. It was not on for longer than those 30 minutes.
B: The burner has heated the solution on for 30 minutes.
This means that the burner has been on for at least 30 minutes and is still on. It carries on into the moment of speaking.

Slide 7 - Slide

Let's practise

For the following sentences. Please indicate whether the action is still ongoing or finished. Simply answer either A or B for each sentence.

Slide 8 - Slide

Let's practise

For the following sentences. Please indicate whether the action is still ongoing or finished. Simply answer either A or B for each sentence.
Consider the first example when looking at these sentences. What patterns can you find? Is there a difference between how the verbs end or when it includes "has/have"?

Slide 9 - Slide


We have learned about lab safety with Mr ten Lohuis for a year.
A
Ongoing
B
Finished

Slide 10 - Quiz


I handed in part of the lab journal yesterday.
A
Ongoing
B
Finished

Slide 11 - Quiz


The pH value increased by a lot.
A
Ongoing
B
Finished

Slide 12 - Quiz


The power outage has lasted for three hours.
A
Ongoing
B
Finished

Slide 13 - Quiz

Let's take it a step further

For the next few sentences, complete the sentence to tell the reader whether it's an ongoing or finished process.

Slide 14 - Slide

The sample ___ in the freezer for a day.
[to rest - ongoing]

Slide 15 - Open question

She ___ the ovens this morning
[to clean - finished]

Slide 16 - Open question

Time to apply what you've learned so far
 
Create sentences using the following words in order to describe tasks you would do in a laboratory.

Slide 17 - Slide

To sterilise
Since this morning

Slide 18 - Open question

To distill
Last month

Slide 19 - Open question

To filter
At 8 o'clock

Slide 20 - Open question

To prepare
For several days

Slide 21 - Open question

Step 1
Write a sentence describing one of the things you do in your lab classes. Make sure to decide whether the action is ongoing or finished. Think of the previous examples and make your own sentence.
Step 2
After writing your sentence, exchange your work with a classmate. Check if you can understand each others sentence and if you can tell whether your partner's process is finished or ongoing.

Slide 22 - Slide