__________ he doesn’t come to my birthday?
Children found the lecture so hard _______that they felt sleepy.
_______,when Marx was already _______,he found it was important to study the situation in Russia, so he began to learn Russian.
—We can not bring any snacks at the sports meeting.—_______.
It was _______ problem that _______ of the students could work it out.
Paul is really considering __ himself to __ those children in the earthquake-hit area.