请教一道GWD语法题！

A surge in new home sales and a drop in weekly unemployment claims suggest that the economy might not be as weak as some analysts previously thought.

1. claims suggest that the economy might not be as weak as some analysts previously thought
2. claims suggests that the economy might not be so weak as some analysts have previously thought
3. claims suggest that the economy might not be as weak as have been previously thought by some analysts
4. claims, suggesting about the economy that it might not be so weak as previously thought by some analysts
5. claims, suggesting the economy might not be as weak as previously thought to be by some analysts

请问B为什么不对？？

请问是选A吧？我觉得B错在：

1），时态不应该用完成式，题目没有哪个标志（如within the past few years等）表示应该换成完成时的，见previously一般都用一般过去式。

2）
                as**as**, 搭配

不妨记住as somebody previously thought
        ，是经常用到的形式。