先期违约
参考答案：
在合同订立之后履行期到来之前，一方表示拒绝履行合同的意图。
So lost in their computers____that leaders at summer computer camps often have to force them to break for sports and games.
A．became the children
B．become the children
C．had the children become
D．do the children become
高温高压下的岩浆从地下深处侵人地壳或喷出地表冷凝而成的岩石叫（）。
A.变质岩
B.岩浆岩
C.石英岩
D.石灰岩
