—Who______ it be that is knocking at the door? —It ______ be Father, but I’m not sure.
______himself to his research on the IT technology, he soon made a breakthrough.
_____the cause of the oil leaks, the specialists can not draw a conclusion before completing a thorough and detailed investigation.
-–What do you think of the lecture?--____but interesting, but I’ve managed to survive it.
English teachers are supposed ______their students a test in class, even after class, ______better teaching results.
I’m certain you’d rather she was opposed to my proposal,______