1. Continuous and Perfect Tenses
Present Continuous Tense
The present continuous tense is used to describe actions or conditions that are taking place at the present time, and for a period of time which includes the present time.
Time markers generally used for present time are: now, this moment, these days, nowadays, or simply use the continuous tense in a sentence.
The formula of present continuous tense: Subject + verb to be (is, am, are) + verb (type I) + ing

2. Examples:
The virus diseases are attacking citrus farm in Kumpeh Ulu, Jambi.
Farmers in Kayu Aro are growing potatoes, carrots and other vegetables.
The extension officer is presenting the methods of making compost.
Budi is doing intercropping between lettuce and baby corn.
I am cultivating my land by using hand-tractor.

3. Past Continuous Tense
The past continuous tense is seldom used alone in a sentence. This type of tense is usually used in combination with an event in the past, which is stated or simply implied.
The formula of past continuous tense: Subject + verb to be (was, were) + verb (type I) + ing.
Examples:
For an action happening in the past:
Tono was spraying the rice field with insecticides.
For two actions happening at the same time in the past:
Tono was spraying the rice field while his wife was clearing the weeds.
For two actions happening in the past, one was continuing while the other interrupted:
Tono and his wife were working the rice field when the flood suddenly came yesterday.

4. Present Perfect Tense
For a completed action or state at an indefinite time in the past. The time markers usually used are: just, already, yet, not yet, etc.
For an action or state that has continued for a period of time, from the point in the past until the present time (past-to-present). The time markers used are: since, for, so far, up to now, in all (time), until now, etc.
The formula of present perfect tense: Subject + have/has + verb (type III).

5. Examples:
Ani has taken the Agricultural Extension course for nearly one semester.
Mr. Madjid has already sold his farm products in the local market with a good price.
I have learned the breeding of tropical vegetables through genetic engineering since many years.
Anton and Susan have demonstrated the techniques of plant propagation by vegetative methods.
Some horticultural products have been rotten during transportation from field to market due to high temperature.

6. Past Perfect Tense
The past perfect tense is used to show an action that was completed before a particular event that also took place in the past.
In a sentence, the past perfect tense is generally combined with a past tense, since both refer to events in the past. The time markers usually used in this combination are: before, after or when.
The formula of past perfect tense: Subject + had + verb (type III).

7. Examples:
Jono had sold his buffaloes before he bought a hand-tractor for cultivating the rice field.
Farmers in our village had cleared the weeds, bush and other materials before they cultivated the land using a hand-tractor.
They sprayed the pesticide after the aphids had attacked their tomato crops.
My uncle grew soybean after he had harvested the cabbages.
The birds had left when the farmer put up the scarecrow.

8. Sentence Transformation
Present and Past Continuous Tenses
To transform sentences in the form of present and past continuous tenses into a negative, simply put the word not after the verb to be; and
To transform the sentences into an interrogative, you should place the verb to be in the front of the statement (at the beginning of the sentence before the subject) or use the question words.

9. Sentence Transformation for Present and Past Perfect Tense
To transform sentences in the form of present and past continuous tenses into a negative, simply put the word not after the verb to be; and
To transform the sentences into an interrogative, you should place the verb to be in the front of the statement (at the beginning of the sentence before the subject) or use the question words.

10. Assignment
My family and I ……….. (fly) from Jakarta to Sidney on Qantas Airlines last year, and we ……….. (watch) a movie on the aircraft during the travel. This movie shows us the lives of farmers in a small town in Western Australia. There ……….. (to be) a man ……….. (stand) on nearby a shade. He ……….. (wear) a blue shirt and a striping jumper. The man ……….. (watch) his workers work in his farm by using modern equipments, such as tractors, drying machine, silos. Some people ……….. (harvest) wheat crops using harvesting tractors, while some others ……….. (unload) the harvested wheat from tractors and ……….. (take) them to the silos for storage. While their parents ……….. (work) on the field, the children ……….. (play) hide-and-seek in the hay. They ……….. (run) here and there happily. I think they ……….. (to be) really ……….. (enjoy) their lives as farmers.