became后加什么介词

　　In the 1990s the area became a magnet for new investment.

　　这个地区在20世纪90年代成了新的投资热点。

　　She only became coherent again two hours after the attack.

　　她发病两小时之后才恢复了清楚地说话的能力。

　　It soon became clear that the programme was a failure.

　　没多久便可清楚地看出，这个节目不受欢迎。

　　I worked there so long that I became part of the furniture.

　　我在那里工作得太久，都不为人注意了。