2. W mojej książce grammar lab jest np napisane że provided that nie mogę użyć w 3 trybie a z resztą jest ok.
"Provided that" is very formal. “If” can be substituted for any “provided that”, but not the other way around:
We won’t enjoy the picnic if it rains. O.K.
We won’t enjoy the picnic provided that it rains. Not O.K.
Sue loves Tom, but she’ll divorce him if he keeps seeing Anna. O.K.
Sue loves Tom, but she’ll divorce him provided that he keeps seeing Anna. Not O.K.
Sue loves Tom, but she’d divorce him if he kept seeing Anna. O.K.
Sue loves Tom, but she’d divorce him provided that he kept seeing Anna. Not O.K.
Sue loved Tom, but she would have divorced him if he had kept seeing Anna. O.K.
Sue loved Tom, but she would have divorced him provided that he had kept seeing Anna. Not O.K.
Sue loved Tom, and she wouldn’t have divorced Tom provided that he hadn’t kept seeing Anna. O.K.