Короткі теоретичні відомості

1. Memorize the following words:

length	довжина
depth	глибина
scale	шкала
jaw	кулачок, губка
screw	гвинт, закручувати
rod	стержень, тяга
thimble	барабан мікрометра, ківш
spindle	шпиндель
thread plug gauge	різьбовий калібр
holder	ручка, утримувач
recess	заглиблення

2. Read and translate the text.

MEASURING TOOLS

Steel rulers serve for determining the length and sometimes the depth of the part to be measured. Steel rulers are graduated in millimeters, but in the USA and England they are graduated in thirty-seconds and sixty-fourths of an inch.

The outside calipers are the simplest instruments for measuring external diameters of the part. The outside caliper consists essentially of two curved legs.

The inside calipers are used for determining the internal diameters of the part. Its construction is almost similar to that of the outside calipers. Sometimes the outside calipers may be used for measuring internal diameters of the part. The outside and inside caliper measurements may be read by placing the legs of the calipers on a ruler and placing one leg and the end of the ruler against a flat surface.

Vernier calipers can be used for measuring both external and internal sizes of a part. By using vernier calipers measurements up to .001 may be determined. Vernier calipers consist of a primary steel scale and four jaws. Two jaws are integral with the scale and two jaws are attached to the frame sliding along the scale. The frame may be clamped on the scale in any position by means of an adjusting screw. The depth of recesses is measured with a depth rod. A vernier on the frame serves for measuring fractional parts of a millimetre.

3. Answer the following questions.

1) When do we use steel rulers?

2) What is the use of outside calipers?

3) What is the difference between outside and inside calipers?

4) When can vernier calipers be used?

4. Memorize the following grammar material:

PRESENT PERFECT CONTINUOUS TENSE

(Теперішній завершено-тривалий час)

+) Стверджувальна форма

I, we, you, they	have been V1+ing
he, she, it	has been V1+ing

–) заперечна форма

I, we, you, they	have not been V1+ing
he, she, it	has not been V1+ing

?) питальна форма

…Have	I, we, you, they	been V1+ing
… Has	he, she, it	been V1+ing

Цей час означає теперішню дію, яка почалась у минулому і триває до цього часу. Перекладаємо теперішньою дією. Уживається зі словами: протягом години – for an hour, протягом місяця – for a month, довгий час – for a long time, з учорашнього дня – since yesterday, з 5 годин – since 5 o’clock, як довго – how long, з якого часу – since when.

For example: I have been working hard since morning. They have not been working here for a long time. Where have you been working for a month?