1. SMS is (сказуемое, глагол-связка) one for the most-used services in second-generation mobile telecommunications systems.
2. Portability does (вспомогательный, усилительный) in fact promote competition, it drives down prices, and keeps providers competitive.
3. We have (смысловой) a lot of problems with existing equipment.
4. However, this methodology has (вспомогательный) proven to be (часть сказуемого) disadvantageous to the
CATV companies, because it is (сказуемое, глагол-связка) extremely difficult to send signals
upstream.
5. My friend is (сказуемое, эквивалент модального) to finish working at the mashine by June.