一楼——第2句楼主明显打错了字居然还能分析?
1.that was a pleasant surprise!
这个一楼分析没错.pleasant是形容词,surprise是名词,形容词修饰名词
2.it am pleasantly surprised!句首应该是I,而不是it:
I am pleasantly surprised!我很吃惊（惊喜）.
pleasantly 是副词修饰surprised.而这里 surprised是动词被动语态,而不是形容词.
surprise sb.:使某人惊喜,
例如：your answer surprised me.你的答案让我惊喜.
sb.be surprised:某人被惊（喜）——某人很惊喜.
I am surprised by your answer.我被你的答案惊（喜）了,即：你的答案让我惊喜.