1. Spot the form. Find the forms of the Past Perfect Continuous in the sentences and underline them. Say what indicates duration (for / since / by the time). a) Mendeleev had been working on his table for months. b) By the time the lecture began, the students had been reading about Lomonosov. c) He had been doing research since Monday.

Перевод задания: Найдите в предложениях формы Past Perfect Continuous и подчеркните их. Укажите, что обозначает длительность (for / since / by the time).

1. Mendeleev had been working on his table for months. — Менделеев работал над своей таблицей в течение нескольких месяцев. Форма: had been working; длительность обозначает for.

2. By the time the lecture began, the students had been reading about Lomonosov. — К тому времени, как началась лекция, студенты читали о Ломоносове. Форма: had been reading; by the time указывает на момент, к которому действие уже продолжалось.

3. He had been doing research since Monday. — Он занимался исследованиями с понедельника. Форма: had been doing; длительность обозначает since.