# 小绿鲸英文文献阅读器（平板） vs PhD Challenge

The clearest difference is in-app purchases: 小绿鲸英文文献阅读器（平板） at none against PhD Challenge's 3. 小绿鲸英文文献阅读器（平板） also leads on iOS requirement (15.1 vs 17.0). On price, update cadence, ads and device support there is nothing between them.

Both are free to download. PhD Challenge sells 3 one-off in-app purchases. 小绿鲸英文文献阅读器（平板） asks for nothing beyond the download.

小绿鲸英文文献阅读器（平板） ships an update every 6 weeks, PhD Challenge every 3 weeks. The most recent releases landed on October 24, 2026 and October 21, 2026 respectively.

## The numbers

| Metric | 小绿鲸英文文献阅读器（平板） | PhD Challenge |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[3.5 (2 ratings)](https://appshunter.io/ios/app/id6450911529/reviews)** | — |
| Number of ratings | **2** | — |
| Positive reviews | 0.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 6 weeks | **Every 3 weeks** |
| Size | 84 MB | 37 MB |
| Requires iOS | **15.1** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [见鲸科技(南京)有限公司](https://appshunter.io/developer/1695096543) | [智慧 吴](https://appshunter.io/developer/1894708009) |

## What reviewers say

### 小绿鲸英文文献阅读器（平板）

[App page](https://appshunter.io/ios/app/id6450911529)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


### PhD Challenge

[App page](https://appshunter.io/ios/app/phd-challenge/id6815483993)

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| 1 Retake Ticket | $0.99 | one-time |
| 5 Retake Tickets | $2.99 | one-time |
| Unlimited Retakes | $9.99 | one-time |


## Frequently asked questions

### Is 小绿鲸英文文献阅读器（平板） free?

小绿鲸英文文献阅读器（平板） is free to download, with no in-app purchases.

### Is PhD Challenge free?

PhD Challenge is free to download, with in-app purchases available.

### Do 小绿鲸英文文献阅读器（平板） or PhD Challenge have ads?

Neither 小绿鲸英文文献阅读器（平板） nor PhD Challenge shows ads.

### Which is updated more often, 小绿鲸英文文献阅读器（平板） or PhD Challenge?

小绿鲸英文文献阅读器（平板） ships an update every 6 weeks, and PhD Challenge every 3 weeks. Most recently, 小绿鲸英文文献阅读器（平板） was updated on October 24, 2026 and PhD Challenge on October 21, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*